Circumference and Area of Circles & Semi-Circles

Front

What is the definition of diameter?

Back

The distance across the circle through the center.

Front

What is the formula for finding the area of a semi-circle?

Back

A = π r² / 2

Front

What is the formula for finding diameter?

Back

d = 2 r

Front

What is the distance across a circle through the center called?

Back

Diameter

Front

What is the formula for finding the circumference of a circle?

Back

C = 2 π r

Front

If the radius of a circle is 7 cm, what is the diameter?

Back

14 cm

Front

If the diameter of a circle is 10 cm, what is the radius?

Back

5 cm

Front

What is the circumference of a circle with a radius of 5 cm?

Back

31.42 cm

Front

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

Back

28.26 cm²

Front

How do you calculate the circumference of a semi-circle?

Back

C = π r + d (where d is the diameter).