Solution: Given vertices of the triangle are A(-5,3), B(p,-1) and C(6,q). Co-ordinates of centroid are (1,-1). Co-ordinates of the centroid of a triangle, whose vertices are (x1,y1), (x2,y2) and...
Two vertices of a triangle are (3, – 5) and ( – 7, 4). Find the third vertex given that the centroid is (2, – 1).
Solution: Let third vertex be C(x3,y3). Given (x1,y1) = (3,-5) (x2,y2) = (-7,4) Co-ordinates of centroid are (2,-1) Co-ordinates of the centroid of a triangle, whose vertices are (x1,y1), (x2,y2)...
Find the co-ordinates of the centroid of a triangle whose vertices are A ( – 1, 3), B(1, – 1) and C (5, 1) (2006)
Solution: Given vertices of the triangle are A(-1,3), B(1,-1) and C(5,1) Co-ordinates of the centroid of a triangle, whose vertices are (x1,y1), (x2,y2) and (x3,y3) are [(x1 + x2+ x3)/3, (y1 + y2+...
The mid-point of the line segment AB shown in the adjoining diagram is (4, – 3). Write down the co-ordinates of A and B.
Solution: Let P(4,-3) be the midpoint of line joining the points A and B. Since A lies on X axis, its co-ordinates are (x2,0) Since B lies on Y axis, its co-ordinates are (0,y1) By midpoint formula,...
A (2, 5), B ( – 1, 2) and C (5, 8) are the vertices of a triangle ABC. P and Q are points on AB and AC respectively such that AP : PB = AQ : QC = 1 : 2. (i) Find the co-ordinates of P and Q. (ii) Show that PQ = 1/3 BC
(i) Given vertices of the ABC are A(2,5), B(-1,2) and C(5,8). P and Q are points on AB and AC respectively such that AP:PB = AQ :QC = 1:2. P(x,y) divides AB in the ratio 1:2. x1= 2, y1 = 5 x2 = -1,...
A (10, 5), B (6, – 3) and C (2, 1) are the vertices of triangle ABC. L is the mid point of AB, M is the mid-point of AC. Write down the co-ordinates of L and M. Show that LM = ½ BC.
Solution: Given points are A(10,5), B(6,-3) and C(2,1). Let L(x,y) be the midpoint of AB. Here x1= 10, y1 = 5 x2 = 6, y2 = -3 By midpoint formula, x = (x1+x2)/2 x = (10+6)/2 = 16/2 = 8 By midpoint...
Find the value of p for which the points ( – 5, 1), (1, p) and (4, – 2) are collinear. Solution:
Let A(-5,1) divides the line joining (1,p) and (4,-2) in the ratio m:n Then by section formula, x = (mx2+nx1)/(m+n) -5 = (m×4+n×1)/(m+n) -5 = (4m+n)/(m+n) -5m-5n = 4m+n -9m = 6n m/n = -9/6 = -2/3...
Show by section formula that the points (3, – 2), (5, 2) and (8, 8) are collinear.
Solution: Let the point B(5,2) divides the line joining A(3,-2) and C(8,8) in the ratio m:n. Then by section formula, x = (mx2+nx1)/(m+n) 5 = (m×8+n×3)/(m+n) 5 = (8m+3n)/(m+n) 5m+5n = 8m+3n 2n = 3m...
Find the coordinates of the vertices of the triangle the middle points of whose sides are (0, ½ ) , ( ½ , ½) and ( ½ , 0).
Let A(x1,y1), B(x2,y2) and C(x3,y3) be the vertices of the triangle ABC. Consider AB By midpoint formula, (x1+x2)/2 = 0 x1+x2 = 0 x1 = -x2 ..(i) By midpoint formula, (y1+y2)/2 = ½ y1+y2 = 1 …(ii)...
Find the third vertex of a triangle if its two vertices are ( – 1, 4) and (5, 2) and midpoint of one sides is (0, 3).
Let A (-1,4) and B(5,2) are the vertices of the triangle and let D(0,3) is the midpoint of side AC. Let co-ordinate of C be (x,y). Consider D(0,3) as midpoint of AC By midpoint formula, (-1+x)/2 = 0...
Prove that the points A ( – 5, 4), B ( – 1, – 2) and C (5, 2) are the vertices of an isosceles right angled triangle. Find the co-ordinates of D so that ABCD is a square.
Given points are A(-5,4), B(-1,-2) and C(5,2) are given. Since these are vertices of an isosceles triangle ABC then AB = BC. By distance formula, d(AB) = √[(x2-x1)2+(y2-y1)2] Here x1 = -5, y1 = 4...
If two vertices of a parallelogram are (3, 2) ( – 1, 0) and its diagonals meet at (2, – 5), find the other two vertices of the parallelogram.
Solution: Let A(3,2) and B(-1,0) be the two vertices of the parallelogram ABCD. Let M(2,-5) be the point where diagonals meet. Since the diagonals of the parallelogram bisect each other, M is the...
If the points A ( – 2, – 1), B (1, 0), C (p, 3) and D (1, q) form a parallelogram ABCD, find the values of p and q.
Given vertices of the parallelogram are A(-2,-1), B(1, 0), C(p,3) and D(1,q). Let M(x,y) be the midpoint of the diagonals of the parallelogram ABCD. Diagonals AC and BD bisect each other at M. When...
Three consecutive vertices of a parallelogram ABCD are A (1, 2), B (1, 0) and C (4, 0). Find the fourth vertex D.
Solution: Let M be the midpoint of the diagonals of the parallelogram ABCD. Co-ordinate of M will be the midpoint of diagonal AC. Given points are A(1,2), B(1,0) and C(4,0). Consider line AC. x1 =...
Calculate the length of the median through the vertex A of the triangle ABC with vertices A (7, – 3), B (5, 3) and C (3, – 1).
Solution: Let M(x,y) be the median of ΔABC through A to BC. M will be the midpoint of BC. x1 = 5, y1 = 3 x2 = 3, y2 = -1 By midpoint formula, x = (x1+x2)/2 x = (5+3)/2 = 8/2 = 4 By midpoint formula,...
(i) Write down the co-ordinates of the point P that divides the line joining A ( – 4, 1) and B (17,10) in the ratio 1 : 2.(iii)In what ratio does the y-axis divide the line AB ?
(iii)Let m:n be the ratio in which Y axis divide line AB. Since AB touches Y axis, its x co-ordinate will be zero. Here x1 = -4, y1 = 1 x2 = 17, y2 = 10 By section formula, x = (mx2+nx1)/(m+n) 0 =...
(i) Write down the co-ordinates of the point P that divides the line joining A ( – 4, 1) and B (17,10) in the ratio 1 : 2. (ii)Calculate the distance OP where O is the origin.
Solution: (i)Let P(x,y) divides the line segment joining the points A(-4,1), B(17,10) in the ratio 1:2, Here x1 = -4, y1 = 1 x2 = 17, y2 = 10 m:n = 1:2 By section formula, x = (mx2+nx1)/(m+n) x =...
Given a line segment AB joining the points A ( – 4, 6) and B (8, – 3). Find:(iii)the length of AB.
(iii) By distance formula, d(AB) = √[(x2-x1)2+(y2-y1)2] d(AB) = √[(8-(-4))2+(-3-6)2] d(AB) = √[(12)2+(-9)2] d(AB) = √(144+81) d(AB) = √225 d(AB) = 15 Hence the length of AB is 15...
Given a line segment AB joining the points A ( – 4, 6) and B (8, – 3). Find: (i) the ratio in which AB is divided by the y-axis. (ii) find the coordinates of the point of intersection.
Solution: (i) Let m:n be the ratio in which the line segment joining A (-4,6) and B(8,-3) is divided by the Y axis. Since the line meets Y axis, its x co-ordinate is zero. Here x1 = -4, y1 = 6 x2 =...
(i) Calculate the ratio in which the line segment joining (3, 4) and( – 2, 1) is divided by the y-axis. (ii) In what ratio does the line x – y – 2 = 0 divide the line segment joining the points (3, – 1) and (8, 9)? Also, find the coordinates of the point of division.
Solution: (i) Let m:n be the ratio in which the line segment joining (3,4) and (-2,1) is divided by the Y axis. Since the line meets Y axis, its x co-ordinate is zero. Here x1 = 3, y1 = 4 x2 = -2,...
If A ( – 4, 3) and B (8, – 6), (i) find the length of AB. (ii) in what ratio is the line joining AB, divided by the x-axis? (2008)
Solution: (i) Given points are A(-4,3) and B(8,-6). Here x1 = -4, y1 = 3 x2 = 8, y2 = -6 By distance formula, d(AB) = √[(x2-x1)2+(y2-y1)2] d(AB) = √[(8-(-4))2+(-6-3)2] d(AB) = √[(12)2+(-9)2] d(AB) =...
The line segment joining A (2, 3) and B (6, – 5) is intercepted by the x-axis at the point K. Write the ordinate of the point k. Hence, find the ratio in which K divides AB. Also, find the coordinates of the point K.
Solution: Since the point K is on X axis, its y co-ordinate is zero. Let the point K be (x,0). Let the point K divides the line segment joining A(2,3) and B(6,-5) in the ratio m:n. Here x1 = 2 ,...
(i) In what ratio does the point (5, 4) divide the line segment joining the points (2, 1) and (7 ,6) ? (ii) In what ratio does the point ( – 4, b) divide the line segment joining the points P (2, – 2), Q ( – 14, 6) ? Hence find the value of b.
Solution: (i) Let the ratio that the point (5,4) divide the line segment joining the points (2,1) and (7,6) be m:n, Here x1 = 2 , y1 = 1 , x2 = 7, y2 = 6, x = 5, y = 4 By section formula, x =...
The point P ( – 4, 1) divides the line segment joining the points A (2, – 2) and B in the ratio of 3 : 5. Find the point B.
Solution: Let the co-ordinates of B be (x2,y2). Given co-ordinates of A = (2,-2) Co-ordinates of P = (-4,1) Ratio m:n = 3:5 x1 = 2, y1 = -2, x = -4, y = 1 P divides AB in the ratio 3:5 By section...
The line segment joining A(-1,5/3) the points B (a, 5) is divided in the ratio 1 : 3 at P, the point where the line segment AB intersects y-axis. Calculate (i) the value of a (ii) the co-ordinates of P. (1994)
Solution: (i) Let P(x,y) divides the line segment joining the points A(-1,5/3), B(a,5) in the ratio 1:3, Here m:n = 1:3 x1 = -1 , y1 = 5/3 , x2 = a, y2 = 5 By Section formula x = (mx2+nx1)/(m+n) x =...
Find the reflection (image) of the point (5, – 3) in the point ( – 1, 3).
Solution: Let the co-ordinates of the image of the point P(5,-3) be P1(x, y) in the point (-1, 3) then the point (-1, 3) will be the midpoint of PP1. By midpoint formula, x = (x1+x2)/2 -1 = (5+x2)/2...
AB is a diameter of a circle with centre C ( – 2, 5). If point A is (3, – 7). Find: (i) the length of radius AC. (ii) the coordinates of B.
(i) Length of radius AC = d(A,C) Co-ordinates of A = (3,-7) Co-ordinates of C = (-2,5) Here x1 = 3, y1 = -7, x2 = -2, y2 = 5 By distance formula, d(A,C) = √[(x2-x1)2+(y2-y1)2] = √[(-2-3)2+(5-(-7))2]...
The co-ordinates of the mid-point of the line segment PQ are (1, – 2). The co-ordinates of P are ( – 3, 2). Find the co-ordinates of Q.(1992)
Solution: Let the co-ordinates of Q be (x2, y2). Given co-ordinates of P = (-3,2) Co-ordinates of midpoint = (1,-2) Here x1 = -3, y1 = 2 , x = 1 , y = -2 By Midpoint formula, x = (x1+x2)/2 1 =...
The mid-point of the line segment joining the points (3m, 6) and ( – 4, 3n) is (1, 2m – 1). Find the values of m and n.
Solution: Let the midpoint of line joining the points A(3m,6) and B(-4,3n) be C(1,2m-1). Here x1 = 3m, y1 = 6 , x2 = -4, y2 = 3n x = 1 , y = 2m-1 By Midpoint formula, x = (x1+x2)/2 1 = (3m+-4)/2...
Use graph paper for this question. Take 1 cm = 1 unit on both axes. Plot the points A(3, 0) and B(0, 4).(v) Assign the special name to quadrilateral ABC1B1.
(v) In quadrilateral ABC1B1, ABB1C1 Hence the quadrilateral ABC1B1 is a trapezium.
Use graph paper for this question. Take 1 cm = 1 unit on both axes. Plot the points A(3, 0) and B(0, 4).(iii) Assign the special name to the quadrilateral ABA1B1. (iv) If C is the midpoint is AB. Write down the co-ordinates of the point C1, the reflection of C in the origin.
(iii) The quadrilateral ABA1B1 will be a rhombus. (iv) Let C be midpoint of AB. Co-ordinate of C = ((3+0)/2 , (0+4)/2) = (3/2, 2) [Midpoint formula] In a point reflection in the origin, the image of...
Use graph paper for this question. Take 1 cm = 1 unit on both axes. Plot the points A(3, 0) and B(0, 4). (i) Write down the co-ordinates of A1, the reflection of A in the y-axis. (ii) Write down the co-ordinates of B1, the reflection of B in the x-axis.
(i) Co-ordinates of point A are (3,0). When you reflect a point across the Y-axis, the y-coordinate remains the same, but the x-coordinate is transformed into its opposite (its sign is changed)...
Point P (3, – 5) is reflected to P’ in the x- axis. Also P on reflection in the y-axis is mapped as P”. (iii) Find the middle point of the line segment P’ P”. (iv) On which co-ordinate axis does the middle point of the line segment P P” lie ?
(iii) Co-ordinates of P’ = (3,5) Co-ordinates of P’’ = (-3,-5) Here x1 = 3, y1 = 5 , x2 = -3, y2 = -5 Let Q(x,y) be the midpoint of P’P’’ By midpoint formula, x = (x1+x2)/2 y = (y1+y2)/2 x =...
Point P (3, – 5) is reflected to P’ in the x- axis. Also P on reflection in the y-axis is mapped as P”. (i) Find the co-ordinates of P’ and P”. (ii) Compute the distance P’ P”.
Solution: (i) The image of P(3,-5) when reflected in X-axis will be (3,5). When you reflect a point across the X-axis, the x-coordinate remains the same, but the y-coordinate is transformed into its...
Find the coordinates of the point which is three-fourth of the way from A (3, 1) to B ( – 2, 5).
Let P be the point which is three-fourth of the way from A(3,1) to B(-2,5). AP/AB = 3/ 4 AB = AP+PB AP/AB = AP/(AP+PB) = 3/4 4AP = 3AP+3PB 4AP-3AP = 3PB AP = 3PB AP/PB = 3/1 The ratio m:n = 3:1 x1 =...
(i) The line segment joining the points A (3, 2) and B (5, 1) is divided at the point P in the ratio 1 : 2 and it lies on the line 3x – 18y + k = 0. Find the value of k. (ii) A point P divides the line segment joining the points A (3, – 5) and B ( – 4, 8) such that AP/PB = k/1 If P lies on the line x + y = 0, then find the value of k.
Solution: (i) Let the co-ordinates of P(x, y) divides AB in the ratio m:n. A(3,2) and B(5,1) are the given points. Given m:n = 1:2 x1 = 3 , y1 = 2 , x2 = 5 , y2 = 1 , m = 1 and n = 2 By Section...
(i) Find the co-ordinates of the points of trisection of the line segment joining the point (3, – 3) and (6, 9). (ii) The line segment joining the points (3, – 4) and (1, 2) is trisected at the points P and Q. If the coordinates of P and Q are (p, – 2) and (5/3, q) respectively, find the values of p and q.
Let P and Q be the points of trisection of AB i.e., AP = PQ = QB Given A(3,-3) and B(6,9) x1 = 3, y1 = -3, x2 = 6, y2 = 9 P(x, y) divides AB internally in the ratio 1 : 2. m:n = 1:2 By applying the...
P divides the distance between A ( – 2, 1) and B (1, 4) in the ratio of 2 : 1. Calculate the co-ordinates of the point P.
Solution: Let the co-ordinates of P(x, y) divides AB in the ratio m:n. A(-2,1) and B(1,4) are the given points. Given m:n = 2:1 x1 = -2 , y1 = 1 , x2 = 1 , y2 = 4 , m = 2 and n = 1 By Section...
The co-ordinates of two points A and B are ( – 3, 3) and (12, – 7) respectively. P is a point on the line segment AB such that AP : PB = 2 : 3. Find the co-ordinates of P.
Solution: Let the co-ordinates of P(x, y) divides AB in the ratio m:n. A(-3,3) and B(12,-7) are the given points. Given m:n = 2:3 x1 = -3 , y1 = 3 , x2 = 12 , y2 = -7 , m = 2 and n = 3 By Section...
Find the co-ordinates of the mid-point of the line segments joining the following pairs of points:(iii) (a + 3, 5b), (2a – 1, 3b + 4)
(iii) Co-ordinates of midpoint of line joining the points (x1,y1) and (x2,y2) = {(x1+x2)/2 ,(y1+y2)/2} Co-ordinates of midpoint of line joining the points (a+3, 5b) and (2a-1,3b+4) = {(a+3+2a-1)/2,...
Find the co-ordinates of the mid-point of the line segments joining the following pairs of points: (i) (2, – 3), ( – 6, 7) (ii) (5, – 11), (4, 3)
Solution: Co-ordinates of midpoint of line joining the points (x1,y1) and (x2,y2) = {(x1+x2)/2 ,(y1+y2)/2} (i) Co-ordinates of midpoint of line joining the points (2, -3) and (-6,7) = {(2+-6)/2,...