Workers plan to apply a reflective coating of paint to one surface of an equilateral triangular shaped highway sign. How many square inches of coating need to be applied to the sign if one side of the triangle is inches?

Question

anonymous · Answer

14 inches

barrycarter · Answer

The height of an equilateral triangle with sides of 14 inches is 14*Sqrt[3]/2 inches (30-60-90 triangle), so the area of the sign is:

 1/2*b*h or

1/2*14*(14*Sqrt[3]/2) or

49*Sqrt[3] or about 84.8705 square inches (round it to 85)