Question

You are making an umbrella that is shaped like a regular octagonal pyramid.

Estimate the amount of fabric that you need to make the umbrella.

Answer 1

80 ft²

Explanation:

From the diagram

The umbrella has a total of 8 triangle.

Applying

A = 8(bh)/2

A = 4bh...................... Equation 2

Where A = Amount of fabric, b = base of one of the triangle in the octagonal pyramid, h = height of the triangle.

From the diagram,

Given: b = 4 ft, h = 5 ft

Substitute these values into equation 2

A = 4×4×5

A = 80 ft²