6.8 Warm-Up

Front

What is π?

Back

The ratio of the circumference of any circle to its diameter.

Front

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

Back

C = π·d

Front

What is the definition of circumference?

Back

The distance around a circle.

Front

What is a radius?

Back

A line from the center of the circle to any point on its circumference.

Front

What is a diameter?

Back

A line from one side of the circle to the other, passing through the center.

Front

How do you calculate the area of a circle?

Back

A = π·r²

Front

What is the relationship between radius and diameter?

Back

The diameter is twice the length of the radius.

Front

If the radius of a circle is 5 cm, what is the diameter?

Back

10 cm

Front

If the circumference of a circle is 31.4 cm, what is the radius?

Back

5 cm (using C = 2πr).

Front

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

Back

A = π·r²