solution;

Given height of the tent above the ground = 85 m

Height of the cylindrical part, H = 50 m

height of the cone, h = 85-50

h = 35 m

Diameter of the base, d = 168 m

Radius of the base of cylindrical part, r = d/2 = 168/2 = 84 m

Radius of cone, r = 84 m

Slant height of the cone, l = √(h²+r²)

l = √(35²+84²)

l = √(1225+7056)

l = √(8281)

l = 91 m

Surface area of tent = curved surface area of cylinder + curved surface area of cone

= 2rH+rl

= r(2H+l)

= (22/7)×84×(2×50+91)

= (22/7)×84×(100+91)

= ((22×84)/7)×191

= (1848/7)×191

= 264×191

= 50424 m²

Adding 20% extra for folds and stitches,

Area of canvas = 50424+ 20% of 50424

= 50424+ (20/100) ×50424

= 50424+ 0.2×50424

= 50424+ 10084.8

= 60508.8 m²

= 60509 m²

Hence the the quantity of canvas required to make the tent is 60509 m².