Step-by-step explanation:

1.) We know that C = πd. Since the diameter is 10cm, we know that C = π × 10cm = 31.42 (to 2 decimal places.

2.)As diameter is double the radius, if diameter is 40 meters, radius of circle is 20 meters. Hence circumference of circle is 2×3.1416×20=125.664 meters and area is 3.1416×20×20=1256.64 square meters.

3.)176.7 is the area of a circle and diameter 15

r = 7.5 d = 15 C = 47.1

A=πr²= π(d2)² A=C² 4π π = 3.1415 A =area C = circumference or parameter

r=radius, d=diameter

4.)THE FORMULA FOR CIRCUMFERENCE USING RADIUS Is 2πr 2 π r