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What is the area of an equilateral triangle with sides 12cm?
A. 18√3
B. 36√3
C. 72√3
D. 12√2
E. 54√2
Correct Answer: B
Explanation/Reference:
Explanation:
An equilateral triangle has three congruent sides and results in three congruent angles. This figure results in two special right triangles back to back: 30°-60°-90° giving sides of x – x√3 – 2x in general. The height of the triangle is the x√3 side. So Atriangle = 1/2 bh = 1/2 × 12 × 6√3 = 36√3 cm2.
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