Area and Circumference of Circles

Front

What does d represent in the formula: C = π·d?

Back

Diameter.

Front

What is the formula for the circumference of a circle using diameter?

Back

C = π·d.

Front

What is the formula for the circumference of a circle using radius?

Back

C = 2π·r.

Front

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

Back

25π cm².

Front

What is the circumference of a circle with a diameter of 4 cm?

Back

4π cm.

Front

What is the formula for the area of a circle?

Back

A = π·r².

Front

If the radius of a circle is doubled, how does the area change?

Back

The area increases by a factor of 4.

Front

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

Back

5 cm.

Front

What is the value of π (pi) approximately?

Back

3.14.

Front

How do you convert diameter to radius?

Back

Divide the diameter by 2.