Question

A paved walkway around a garden has an outer diameter of 80 ft and an inner diameter of 40 ft. A diagram is shown below.

Answer 1

Given:

• Outer diameter = D = 80 ft
• Inner diameter = d = 40 ft

So,

Outer radius = R = D/2

=> R = (80 ft)/2

=> R = 40 ft

Inner radius = r = d/2

=> r = (40 ft)/2

=> r = 20 ft

Area of paved pathway = πR² - πr²

= π(R² - r²)

= π(R + r)(R - r)

= π(40 + 20)(40 - 20) ft²

= π(60)(20) ft²

= 3.14 * 1200 ft²

= 3768 ft²