Diameter Dilemma
If the diameter is 8 feet, what is the radius?
4 ft
A circular garden is 6 meters from one side to another. How big around is it?
C=3.14(6)=18.84 m
The radius of a circle is 4 centimeters. What is the circumference?
25.12 cm
Write the formula for circumference using diameter.
C=πd
The diameter of a circle is 12 centimeters. What is its circumference?
37.68 cm
The spoke of a bike wheel is 14 inches from the center to the edge. How far does it roll in one rotation?
C=2πr=2(3.14)(14)=87.92 in
A circle’s radius is 7.5 inches. Find the circumference.
47.1 in
Write the formula you’d use to find a circle's circumference using the radius.
C=2πr
A car wheel has a diameter of 20.8 inches. About how far does the wheel travel in 5 rotations?
327 inches
A circular racetrack from center to edge is 50 meters long. How far does a car travel in 3 laps?
C = l(2πr) = 3(2π50) = 2942 m
A bike wheel has a radius of 13 inches. How far does the wheel travel in 5 rotations?
408 inches
A circular track has a radius of r meters. Write an equation for the distance (d) run in (x) laps.
D=x(2πr)
A circle’s diameter is tripled. How does that affect its circumference?
It is also tripled.
The distance around a circular pond is 94.2 m. How far does a fish have to swim to cross it?
d=C/π=94.2/3.14=30 m
When you double a circle's radius, what is the resulting change in its circumference?
It is also doubled.
A circle’s circumference is 25.12 centimeters. Write an equation to solve for its radius.
r=25.12/2π
A circle has a circumference of 62.8 meters. What is the diameter?
d = C/π = 62.6/π = 20 m
Your dog has escaped, and is running around a circular field. You run 20 feet across to try to catch him. How far does he run in 5 laps?
C = l(πd) = 5(20π) = 314 feet
The circumference of a circle is 31.4 centimeters. What is the radius?
r = C/2π = 31.4/2π = 5 cm
A car wheel's diameter is 20.8 inches. Write an equation relating the distance the car travels in inches, (d), to the number of wheel rotations, (x).
D=x(20.8π)