In figure, DE || BC. If DE = 3 cm, BC = 6 cm and area of ΔADE = 15 sq cm, then the area of ΔABC is
It is given thatDE = 3 cm, BC = 6 cm
Let area of $$\triangle$$ ABC = $$x$$ sq cm and area of $$\triangle$$ ADE = 15 sq cm
In $$\triangle$$ ADE and $$\triangle$$ ABC
$$\angle$$ DAE = $$\angle$$ BAC (common)
$$\angle$$ ADE = $$\angle$$ ABC (Alternate interior angles)
$$\angle$$ AED = $$\angle$$ ACB (Alternate interior angles)
=> $$\triangle$$ ADE $$\sim$$ $$\triangle$$ ABC
=> Ratio of Area of $$\triangle$$ ADE : Area of $$\triangle$$ ABC = Ratio of square of corresponding sides = $$(DE)^2$$ : $$(BC)^2$$
=> $$\frac{15}{x}=\frac{(3)^2}{(6)^2}$$
=> $$\frac{15}{x} = \frac{9}{36}$$
=> $$\frac{15}{x}=\frac{1}{4}$$
=> $$x=15\times4=60$$ $$cm^2$$
=> Ans - (D)
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