# Slant height of a pyramid

• May 11th 2010, 10:08 AM
nosolution680
Slant height of a pyramid
The ratio of the height of the pyramid to the edge of the square base is 1.5 to 1. The height of the pyramid is 3 meters. What is the approximate length of the slant height of the pyramid?

A. 4.4 m
B. 3.2 m
C. 2.8 m
D. 1.4 m

I am not sure what the ratio part means, but I thought maybe
using a proportion
(1.5/1)=(3/x)
so x=2

and then using a triangle (pyth. thm.) 3^2 + 2^2 = c^2 (slant height)
so I got sqrt (13) which equals 3.6

which the answer is supposed to be 3.2 but I do not think I did this correct because the answers are not close enough.
• May 11th 2010, 10:50 AM
dwsmith
Quote:

Originally Posted by nosolution680
The ratio of the height of the pyramid to the edge of the square base is 1.5 to 1. The height of the pyramid is 3 meters. What is the approximate length of the slant height of the pyramid?

A. 4.4 m
B. 3.2 m
C. 2.8 m
D. 1.4 m

I am not sure what the ratio part means, but I thought maybe
using a proportion
(1.5/1)=(3/x)
so x=2

and then using a triangle (pyth. thm.) 3^2 + 2^2 = c^2 (slant height)
so I got sqrt (13) which equals 3.6

which the answer is supposed to be 3.2 but I do not think I did this correct because the answers are not close enough.

2 is the length of base not the length of b in your triangle.