Radius, diameter and area of circles

Front

A straight line from the center of a circle to the circumference is called the ____.

Back

Radius

Front

What is the formula to calculate the area of a circle?

Back

Area = π × radius²

Front

What is the diameter of a circle?

Back

The diameter is twice the length of the radius.

Front

If the radius of a circle is 4 mm, what is the diameter?

Back

8 mm

Front

If the radius of a circle is 35 cm, what is the area? (Use π ≈ 3.14)

Back

Area = 3.14 × (35)² = 3.14 × 1225 = 3848.5 cm²

Front

What is the circumference of a circle?

Back

Circumference = 2 × π × radius

Front

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

Back

5 cm

Front

What is the relationship between radius and diameter?

Back

Diameter = 2 × Radius

Front

If the radius of a circle is 47 cm, what is the area? (Use π ≈ 3.14)

Back

Area = 3.14 × (47)² = 3.14 × 2209 = 6930.46 cm²

Front

What is the area of a circle with a radius of 8 mm? (Use π ≈ 3.14)

Back

Area = 3.14 × (8)² = 3.14 × 64 = 200.96 mm²