Area of a circle

Front

What is the formula for area of a circle given the radius?

Back

A = πr²

Front

What is the value of π (pi)?

Back

3.14

Front

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

Back

A = π(7)² = 153.86 cm²

Front

What is the diameter of a circle if the radius is 5 cm?

Back

Diameter = 2 * radius = 10 cm

Front

How do you find the radius if you know the area of the circle?

Back

Radius = √(Area/π)

Front

What is the area of a circle with a diameter of 10 cm?

Back

A = π(5)² = 78.54 cm²

Front

What is the relationship between radius and diameter?

Back

Diameter = 2 * radius

Front

If the area of a circle is 314 cm², what is the radius?

Back

Radius = √(314/π) ≈ 9.98 cm

Front

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

Back

A = π(4)² = 50.27 cm²

Front

What happens to the area of a circle if the radius is doubled?

Back

The area increases by a factor of 4.