Bunuel

In the figure above, what is the area of the quadrilateral?
(A) 6 + 2√6
(B) 2√30
(C) 11
(D) 13
(E) cannot be determined
Attachment:
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Divide the original figure into two triangles. One is a right triangle, the other, isosceles. Sum their areas.
On original figure, draw a line to connect points A and B, which creates a right triangle and another triangle.
1) Length of hypotenuse, \(c\), of right triangle (AB, the two triangles' shared side)
The right triangle is a \(3-4-5\) right triangle. Hypotenuse = \(5\). OR
\(3^2 + 4^2 = c^2\)
\(25 = c^2\)
\(c = 5\)2) Area of the right triangle
\(\frac{b * h}{2} =\frac{3 * 4}{2} =6\)
3) Area of the other triangle ABC - it is isosceles. One side is the hypotenuse of the other triangle, so side lengths are 5 - 5 - 2
Drop an altitude from top vertex to base.
The altitude of an isosceles triangle divides it into two congruent right triangles. Base of length 2 becomes 1 and 1.
Height? Use one right triangle
\(1^2 + x^2 = 5^2\)
\(x^2 = 24\)
\(x = \sqrt{24} = \sqrt{4 * 6}\)
\(x = 2\sqrt{6}\)
Area of the isosceles triangle ABC:
\(\frac{b*h}{2} = \frac{(2 * 2\sqrt{6})}{2}= 2\sqrt{6}\)
4) Area of quadrilateral:
\(6 + 2\sqrt{6}\)
Answer A