Radius and Diameter
What formula do you use to find radius?
r=1/2d
What is the formula for circumference when you know the radius?
C=2pi r
What is the formula for the area of a circle?
A=pi r^2
What formula would you use to solve the following problem?
A circle has a circumference of 25pi, what is the diameter?
C=pi d
What formula do you use to find diameter?
d=2r
What is the formula for circumference when you know the diameter?
C=pi d
A circle has a radius of 2 ft, what is the area? Leave your answer in terms of pi.
A=4pi ft^2
The circumference of a circle is 64pi, what is the radius?
C=2pi r
The diameter of a circle is 15 in, what is the radius?
r=7.5 in
The radius of a circle is 5 meters, what is the circumference in terms of pi?
C=10pi meters
The diameter of a circle is 10 km. What is the area in terms of pi?
A=25pi km^2
A circle has a circumference of 25pi, what is the diameter?
d=25
The radius of a circle is 3 cm, what is the diameter?
d=6 cm
The diameter of a circle in 8 miles, what is the circumference? Round your answer to the nearest tenth.
25.1 miles
The radius of a circle is 7 in, what is the area? Round to the nearest tenth.
A=153.9 in^2
The circumference of a circle is 64pi, what is the radius?
r=32
HALF of the radius of a circle is 2 ft. What is the radius and diameter?
r=4 ft
d=8 ft
What does the circumference measure?
The distance around the outside of a circle.
The diameter of a circle is 9 mm, what is the area? Round to the nearest tenth.
A=63.6 mm^2
The circumference of a circle is 78mm. Find the radius? Round your answer to the nearest tenth.
r=12.4 mm