Circumference and Area of Circles

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

What is the formula for the circumference of a circle?

Back

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

Tags

CCSS.7.G.B.4

Front

If the area of a circle is 78.5 square inches, what is the radius?

Back

5 inches.

Tags

CCSS.7.G.B.4

Front

If the area of a circle is 200.96 square feet, what is the diameter?

Back

16 feet.

Tags

CCSS.7.G.B.4

Front

What is the relationship between the radius and diameter of a circle?

Back

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

Front

How do you convert area from square inches to square feet?

Back

Divide the area in square inches by 144 (since 1 square foot = 144 square inches).

Front

What is the approximate value of π (pi)?

Back

π is approximately 3.14.

Tags

CCSS.HSG.GMD.A.1

Front

If the radius of a circle is 4 inches, what is the area?

Back

A = π(4)² = 50.24 square inches.

Tags

CCSS.7.G.B.4

Front

If the radius of a circle is 5 inches, what is the circumference?

Back

C = 2π(5) = 31.4 inches.

Tags

CCSS.7.G.B.4

Front

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

Back

A = π(5)² = 78.5 square feet.

Tags

CCSS.7.G.B.4