Circles - Area and Circumference

Front

What is the formula for the circumference of a circle?

Back

C = 2πr, where C is the circumference and r is the radius.

Tags

CCSS.7.G.B.4

Front

What is the formula for the area of a circle?

Back

A = πr², where A is the area and r is the radius.

Tags

CCSS.7.G.B.4

Front

If a circle has a radius of 4, what is its circumference?

Back

8π or about 25.12.

Tags

CCSS.7.G.B.4

Front

If a circle has a radius of 8 inches, what is its circumference?

Back

50.24 inches.

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

What is the relationship between diameter and radius?

Back

The diameter is twice the radius (d = 2r).

Tags

CCSS.7.G.B.4

Front

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

Back

r = C / (2π).

Tags

CCSS.7.G.B.4

Front

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

Back

r = √(A/π).

Tags

CCSS.7.G.B.4

Front

What is the circumference of a circle with a diameter of 10?

Back

C = πd = 10π or about 31.4.

Tags

CCSS.7.G.B.4

Front

What is the area of a circle with a radius of 5?

Back

A = π(5)² = 25π or about 78.5.

Tags

CCSS.7.G.B.4