Area and Circumference of Circles

Front

What is the formula for the area of a circle?

Back

Area = πr², where r is the radius of the circle.

Tags

CCSS.7.G.B.4

Front

What is the formula for the circumference of a circle?

Back

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

Tags

CCSS.7.G.B.4

Front

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

Back

154 cm² (Area = π(7)² = 154 cm²).

Tags

CCSS.7.G.B.4

Front

If a circle has a diameter of 10 m, what is its circumference?

Back

31.4 m (Circumference = πd = π(10) = 31.4 m).

Tags

CCSS.7.G.B.4

Front

What is the value of π (pi) approximately?

Back

π is approximately 3.14.

Tags

CCSS.HSG.GMD.A.1

Front

How do you find the radius if you know the circumference?

Back

Radius = Circumference / (2π).

Tags

CCSS.7.G.B.4

Front

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

Back

113.1 in² (Area = π(6)² = 113.1 in²).

Tags

CCSS.7.G.B.4

Front

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

Back

25.12 m (Circumference = 2π(4) = 25.12 m).

Tags

CCSS.7.G.B.4

Front

If the area of a circle is 78.5 cm², what is its radius?

Back

Radius = √(Area/π) = √(78.5/π) ≈ 5 cm.

Tags

CCSS.7.G.B.4

Front

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

Back

The area increases by a factor of 4 (Area = π(2r)² = 4πr²).

Tags

CCSS.7.G.B.4