Circles Area and Circumference Review

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

Back

The radius is 5 inches, since the radius is half of the diameter.

Tags

CCSS.7.G.B.4

Front

What is the approximate value of π (pi)?

Back

π is approximately 3.14.

Tags

CCSS.HSG.GMD.A.1

Front

How do you calculate the area of a circle with a radius of 2.5 feet?

Back

A = π(2.5)² = π(6.25) ≈ 19.63 square feet.

Tags

CCSS.7.G.B.4

Front

What is the area of a circle with a radius of 30 cm?

Back

A = π(30)² = π(900) ≈ 2827.43 cm².

Tags

CCSS.7.G.B.4

Front

If the circumference of a circle is 25.12 inches, how do you find the diameter?

Back

Use the formula d = C/π. So, d = 25.12/3.14 ≈ 8 inches.

Tags

CCSS.7.G.B.4

Front

What is the difference in the areas of two circles with radii 30 cm and 20 cm?

Back

Area of larger circle = π(30)², Area of smaller circle = π(20)². Difference = π(900 - 400) = π(500) ≈ 1570 cm².

Tags

CCSS.7.G.B.4

Front

What is the area of a circle with a diameter of 5 feet?

Back

A = π(2.5)² = π(6.25) ≈ 19.63 square feet.

Tags

CCSS.7.G.B.4

Front

How do you find the circumference of a circle with a radius of 4 inches?

Back

C = 2π(4) = 8π ≈ 25.12 inches.

Tags

CCSS.7.G.B.4