Points P and Q lie on side AB and AC of triangle ABC respectively such that segment PQ is parallel to side BC. If the ratio of AP:PB is 2:3, and area of Δ APQ is 8 sq cm, what is the area of trapezium PQCB?
It is given that AP : PB = 2 : 3
Let AP = 2 cm and PB = 3 cm
Let area of trapezium PQCB = $$x$$ sq cm
In $$\triangle$$ APQ and $$\triangle$$ ABC
$$\angle$$ PAQ = $$\angle$$ BAC (common)
$$\angle$$ APQ = $$\angle$$ ABC (Alternate interior angles)
$$\angle$$ AQP = $$\angle$$ ACB (Alternate interior angles)
=> $$\triangle$$ APQ $$\sim$$ $$\triangle$$ ABC
=> Ratio of Area of $$\triangle$$ APQ : Area of $$\triangle$$ ABC = Ratio of square of corresponding sides = $$(AP)^2$$ : $$(AB)^2$$
= $$\frac{(2)^2}{(2 + 3)^2} = \frac{8}{(8 + x)}$$
=> $$\frac{8}{8 + x} = \frac{4}{25}$$
=> $$8 + x = \frac{25 \times 8}{4} = 50$$
=> $$x = 50 - 8 = 42 cm^2$$
=> Ans - (D)
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