Circles - diameter and radius

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 radius of a circle is 7 cm, what is the diameter?

Back

The diameter is 14 cm (Diameter = 2 x Radius).

Front

What is the radius of a circle?

Back

The radius is the distance from the center of the circle to any point on its circumference.

Front

If the diameter of a circle is 20 cm, what is the radius?

Back

The radius is 10 cm (Radius = Diameter / 2).

Front

What is the relationship between diameter and radius?

Back

The diameter is always twice the length of the radius.

Front

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

Back

The diameter is 10 m.

Front

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

Back

Circumference = π x Diameter.

Front

If the diameter of a circle is 30 cm, what is the circumference?

Back

The circumference is approximately 94.25 cm (Circumference = π x 30).

Front

What is the area of a circle with a radius of 4 cm?

Back

The area is 50.27 cm² (Area = π x Radius²).

Front

If the radius of a circle is doubled, what happens to the area?

Back

The area becomes four times larger.