Measuring Circles

Front

What is the formula for the area of a circle?

Back

Area = π × r², where r is the radius.

Front

What is the formula for the circumference of a circle?

Back

Circumference = 2 × π × r, where r is the radius.

Front

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

Back

Radius = Diameter / 2 = 5 cm.

Front

What is the relationship between diameter and radius?

Back

Diameter = 2 × Radius.

Front

How do you calculate the area of a circle with a radius of 7 cm?

Back

Area = π × (7 cm)² ≈ 153.94 cm².

Front

What is the circumference of a circle with a radius of 15 cm?

Back

Circumference = 2 × π × 15 cm ≈ 94.25 cm.

Front

What is the diameter of a circle with a radius of 12 cm?

Back

Diameter = 2 × 12 cm = 24 cm.

Front

How many square feet are in a circle with a radius of 3 feet?

Back

Area = π × (3 ft)² ≈ 28.27 ft².

Front

If a circular garden has a circumference of 31.4 meters, what is its radius?

Back

Radius = Circumference / (2 × π) ≈ 5 meters.

Front

What is the area of a circle with a diameter of 8 inches?

Back

Area = π × (4 in)² ≈ 50.27 in².