Question

The pyramids have always fascinated Kristina, so she wants to build two model pyramids to put on her mantel. She wants her model of Khufu’s pyramid to have a volume of 73.5 cubic inches and a height of 4.5 inches. What would the side length of the base of the pyramid be? Is this number rational or irrational? Why?

Answer 1

7 rational a rational number is a whole number

Explanation:

Answer 2

Side length = 7 inches

This number is a rational number, because it is a whole number and it can be represented as a fraction (7 = 14/2 for example)

Explanation:

The volume of the pyramid can be calculated as:

V = (1/3)*A*h

Where V is the volume, A is the area of the base and h is the height.

If the volume is 73.5 in3 and the height is 4.5 in, we can find the area of the base:

73.5 = (1/3)*A*4.5

A = 73.5*3/4.5 = 49 in2

As the pyramid have a square base, we can calculate the side length of the base:

A = L*L (L = length)

49 = L^2

L = 7 inches

This number is a rational number, because it is a whole number and it can be represented as a fraction (7 = 14/2 for example)