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In the given figure, AB ‖ DC, BO = 6 cm and DQ = 8 cm; find: BP x DO.

Selina Solutions Concise Class 10 Maths Chapter 15 ex. 15(A) - 11

Answer:

In \[\Delta \text{ }DOQ\text{ }and\text{ }\Delta \text{ }BOP,\]

\[\angle QDO\text{ }=\angle PBO\] \[\left[ As\text{ }AB\text{ }\left| \left| \text{ }DC\text{ }in\text{ }this\text{ }way,\text{ }PB\text{ } \right| \right|\text{ }DQ. \right]\]

In this way, \[\angle DOQ\text{ }=\angle BOP\]\[\left[ Vertically\text{ }inverse\text{ }angles \right]\]

Thus, \[\vartriangle DOQ\text{ }\sim\text{ }\vartriangle BOP\]by \[AA\]rule for similitude

Since, relating sides of comparative triangles are corresponding we have

\[DO/BO\text{ }=\text{ }DQ/BP\]

\[DO/6\text{ }=\text{ }8/BP\]

\[BP\text{ }x\text{ }DO\text{ }=\text{ }48\text{ }c{{m}^{2}}\]