What is the are of an equilateral triangle of side 18 cm?
Options:
(A) 663 cm2
(B) 743 cm2
(C) 813 cm2
(D) 645 cm2
(E) 143 cm2 Now, let's think a bit. Some random thoughts:
Area of an equilateral triangle = 3/4 S2
If S = 18, Area of triangle = 3/4 * 18 * 18 = 813 cm2;
The final answer: (C).