Area and Circumference of Circles

Front

What is the formula for the circumference of a circle?

Back

The circumference (C) of a circle is calculated using 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 calculated using the formula: A = πr², where r is the radius.

Front

What is the relationship between diameter and radius?

Back

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

Front

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

Back

The diameter is 20 cm.

Front

If the diameter of a circle is 14 inches, what is the radius?

Back

The radius is 7 inches.

Front

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

Back

The circumference is 31.4 cm (C = 2π(5)).

Front

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

Back

The area is approximately 28.27 m² (A = π(3)²).

Front

How do you convert diameter to radius?

Back

To convert diameter to radius, divide the diameter by 2.

Front

What is the circumference of a circle with a diameter of 12 cm?

Back

The circumference is approximately 37.68 cm (C = π(12)).

Front

If a circle has an area of 50π square units, what is the radius?

Back

The radius is approximately 7.98 units (A = πr², r = √(50)).