CIrcumference & Area of Circles

Front

What is the diameter of a circle?

Back

The diameter is the distance across a circle through its center, equal to twice the radius.

Front

If the diameter of a circle is 19 inches, what is the radius?

Back

The radius is half of the diameter. Therefore, the radius is 9.5 inches.

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

Calculate the area of a circle with a radius of 21 inches.

Back

The area is 1385.44 square inches.

Front

What is the circumference of a circle?

Back

The circumference is the distance around the circle, calculated using the formula C = πd, where d is the diameter.

Front

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

Back

The area is 153.94 cm².

Front

What is the relationship between diameter and radius?

Back

The diameter is twice the length of the radius (d = 2r).

Front

Find the area of a circle with a radius of 3 cm.

Back

The area is 28.26 cm².

Front

What is π (pi)?

Back

π (pi) is a mathematical constant approximately equal to 3.14, representing the ratio of the circumference of a circle to its diameter.

Front

If a circle has a circumference of 31.4 cm, what is its diameter?

Back

The diameter is 10 cm.