Question

Please answer quickly. We know from historical records that the Great Pyramid of Giza was originally about 147 meters tall. Assuming it was built at its faces at 52 degree inclines, what was the original length of one side of its base? Round your answer to nearest meter.
A. 91 meters
B. 115 meters
C. 181 meters
D. 230 meters

Answer 1

x = length of half the base

If you draw out a triangle, the horizontal leg will be x, the vertical leg will be 147 and the angle of inclination (or angle of elevation) is 52 degrees

You'll use tangent to find x

tan(angle) = opposite/adjacent
tan(52) = 147/x
x*tan(52) = 147
x = 147/tan(52)
x = 114.84 ... this is approximate

Half the base is 114.84, so the full base is 2*114.84 = 229.68 which rounds to 230

The final answer is D.