Area and Circumference of a Circle

Front

What is the formula for the area of a circle?

Back

Area = πr², where r is the radius.

Front

What is the formula for the circumference of a circle?

Back

Circumference = 2πr or Circumference = πd, where r is the radius and d is the diameter.

Front

What is the relationship between diameter and radius?

Back

Diameter = 2 × Radius.

Front

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

Back

154 cm² (Area = π × 7²).

Front

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

Back

5 cm (Radius = Diameter / 2).

Front

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

Back

62.83 cm (Circumference = 2π × 10).

Front

What is the value of π (pi) approximately?

Back

3.14.

Front

How do you convert diameter to radius?

Back

Divide the diameter by 2.

Front

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

Back

28.27 m² (Area = π × 3²).

Front

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

Back

5 cm (Circumference = 2πr, so r = 31.4 / (2π)).