Radius & Diameter
The diameter is 10 inches. Find the radius.
5 inches.
A circle has a diameter of 12.5 inches. What is the circumference in terms of pi?
12.5pi inches? or 39.25
The relationship between diameter and radius
d= 2r or r = d/2
A bicycle wheel has a radius of 1 foot. What is the diameter?
2 ft
The diameter is 25 feet. Find the radius.
12.5 feet.
A circle has a diameter of 25 inches. What is the circumference rounded correctly to 2 decimals (no pi in the answer)?
78.54 inches
2*pi*r
circumference
A large Jeep has a tire with a radius of 18 inches. Find the circumference of the wheel.
36pi
or 113.04
The circumference of the circle is 18 inches. Find the radius.
9 inches.
A circle has a radius of 50 miles. What is the area of the circle TO THE NEAREST MILE?
7854 miles squared.
Area of a circle
pi*r^2?
Matt is learning to drive a car. The steering wheel in his car has a radius of 9 inches. His instructor says "Place your hands at 10 and 2." (1/3 of the circle) What is the area of the circle formed in terms of pi?
27pi inches
or 84.78 inches
The area of this circle is 25pi inches squared. Find the radius.
5 inches.
A circle has a diameter of 16. Find the area in terms of pi.
4(y^2)pi
Finding radius when given circumference
C/2pi = r
John owns a circular pool in his back yard. If he swims around the pool, he swims 30pi meters. What is the radius of this circle?
15 meters
C/2pi = r
A circle has an area of 256pi cm squared. Find the diameter.
32cm
A circle has a circumference of 6pi. What is the area?
9pi or 28.26
Finding the area of a circle when given diameter
What is (d/2)^2*pi = A
A circle has a diameter of 28 inches. What is the area of a quarter of the circle? You must give your answer as either a whole number or a decimal
154 (153.86)