Question

Find the area and circumference of a circle with a diameter of 10 in. Round to the nearest tenth for both values.

Answer 1

Answer: area = 0.1 m^2

Circumference = 0.8 m

Explanation:

1 in = 0.0254 m

5 in = 0.0254 m × 5

5 in = 0.127 m

r = 0.127 m

Area of the circle = π r^2

= π × 0.127^2

= 0.05 m^2

=0.1 m^2

Circumference of the circle = 2 π r

= 2× π × 0.127

= 0.798 m

= 0.8 m

Answer 2

1. A = 78.5 in²

2. C = 31.4 in

Explanation:

1. area of a circle = πr²

2. circumference of a circle = 2πr

where diameter = 10 in.

radius = 10 / 2 = 5 in

1. area of a circle = π(5)²

= 78.5 in²

2. circumference of a circle = 2πr

= 2π(5)

= 31.4 in