ABCD is a trapezoid where BC is parallel to AD and perpendicular to AB. Kindly note that BC< AD. P is a point on AD such that CPD is an equilateral triangle. Q is a point on BC such that AQ isĀ parallel to PC. If the area of the triangle CPD is $$4\sqrt{\ 3}$$, find the area of the triangle ABQ.
Given that,Ā CPD is an equilateral triangle
$$\angle\ CPD=\angle\ PDC=\angle\ DCP=60^{\circ\ }$$
As AQ is parallel to PCĀ $$\angle\ CPD=\angle\ QAP=60^{\circ\ }$$
As BC is parallel to ADĀ $$\angle\ QAP=\angle\ AQB=60^{\circ\ }$$ ( alternate interior angles).
Given,Ā Area of equilateral triangle CPD is $$4\sqrt{\ 3}$$
This implies,Ā $$\ \frac{\ \sqrt{3}a^2}{4}=4\sqrt{3}$$
Solving, we getĀ $$a=\ 4$$.
From figure, length of $$AB$$ = Height ofĀ $$\triangle\ CPD=\frac{\sqrt{\ 3}a}{2}=2\sqrt{\ 3}$$.
From $$\triangle\ ABQ,\ BQ=\ \frac{\ AB}{\tan\ 60^{\circ\ }}=\frac{2\sqrt{\ 3}}{\sqrt{\ 3}}=2$$
Area ofĀ $$\triangle\ ABQ=\frac{1}{2}\times\ AB\times\ BQ=\ \ \frac{\ 2\times\ 2\sqrt{\ 3}}{2}=2\sqrt{\ 3}\ $$
Option A is correct.
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