Area and Circumference of a Circle

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 radius of 5 cm, what is its area?

Back

Area = π × (5 cm)² = 78.5 cm².

Front

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

Back

Radius = Diameter / 2 = 10 cm / 2 = 5 cm.

Front

What is the relationship between radius and diameter?

Back

Diameter = 2 × Radius.

Front

If Circle A has a radius of 6 cm and Circle B has a radius of 3 cm, how do their areas compare?

Back

Area of Circle A = 113.1 cm², Area of Circle B = 28.3 cm². Circle A's area is larger.

Front

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

Back

Area = π × (7 cm)² = 153.9 cm².

Front

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

Back

Circumference = 2 × π × 4 cm = 25.1 cm.

Front

If the radius of a circle is doubled, how does the area change?

Back

The area increases by a factor of 4.

Front

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

Back

Area = π × (6 cm)² = 113.1 cm².