Circles: Area and Circumference Practice

Front

What is the formula for the circumference of a circle?

Back

The circumference (C) of a circle is given by the formula: C = 2πr, where r is the radius.

Front

What is the formula for the area of a circle?

Back

The area (A) of a circle is given by the formula: A = πr², where r is the radius.

Front

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

Back

The radius is 5 cm.

Front

What is the value of π (pi) approximately?

Back

π is approximately 3.14.

Front

How do you find the radius from the circumference?

Back

To find the radius (r) from the circumference (C), use the formula: r = C / (2π).

Front

If the area of a circle is 314 cm², what is the radius?

Back

The radius is 10 cm.

Front

What is the relationship between diameter and radius?

Back

The diameter (d) of a circle is twice the radius: d = 2r.

Front

If a circular track has a circumference of 157 meters, what is the radius?

Back

The radius is 25 m.

Front

What is the circumference of a circle with a radius of 10 cm?

Back

The circumference is 62.8 cm.

Front

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

Back

The area is 78.5 cm².