Circumference and Area of Circles

Front

What is the definition of the diameter of a circle?

Back

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

Front

What is the definition of the radius of a circle?

Back

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

Front

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

Back

Circumference = π × diameter or Circumference = 2 × π × radius.

Front

What is the approximate value of π (pi)?

Back

π (pi) is approximately equal to 3.14.

Front

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

Back

The radius is 5 cm.

Front

How do you calculate the area of a circle?

Back

Area = π × radius².

Front

What is the area of a circle with a radius of 7 cm?

Back

Area = π × 7² = 153.86 cm² (approximately).

Front

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

Back

Diameter = Circumference / π = 31.4 / 3.14 = 10 cm.

Front

What is the relationship between diameter and radius?

Back

The diameter is twice the length of the radius.

Front

If a circle has a radius of 4 m, what is its circumference?

Back

Circumference = 2 × π × 4 = 25.12 m (approximately).