Area and Circumference of a Circle

Front

What is the formula for the circumference of a circle?

Back

C = π * d (where C is circumference and d is diameter)

Front

What is the relationship between radius and diameter?

Back

Diameter is twice the radius. (d = 2 * r)

Front

If the radius of a circle is 8 inches, what is the circumference?

Back

50.24 inches

Front

If the diameter of a circle is 19 inches, what is the radius?

Back

9.5 inches

Front

What is the formula for the area of a circle?

Back

A = π * r² (where A is area and r is radius)

Front

If the radius of a circle is 5 inches, what is the area?

Back

78.5 inches²

Front

What is the value of π (pi) approximately?

Back

3.14

Front

How do you calculate the area of a circle if you know the diameter?

Back

First, find the radius (r = d/2), then use A = π * r².

Front

What is the circumference of a circle with a diameter of 10 inches?

Back

31.4 inches

Front

What is the area of a circle with a radius of 3 cm?

Back

28.26 cm²