Area and Circumference of Circles

Front

What is the formula for the circumference of a circle?

Back

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

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

If the radius of a circle is 10 cm, what is the circumference?

Back

C = 2π(10) = 62.8 cm.

Tags

CCSS.7.G.B.4

Front

What is the formula for the area of a circle?

Back

A = πr², where r is the radius.

Tags

CCSS.7.G.B.4

Front

If the radius of a circle is 5 cm, what is the area?

Back

A = π(5)² = 78.5 cm².

Tags

CCSS.7.G.B.4

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

If the diameter of a circle is 20 cm, what is the radius?

Back

r = d/2 = 20/2 = 10 cm.

Tags

CCSS.7.G.B.4

Front

What is the circumference of a circle with a diameter of 12 cm?

Back

C = πd = π(12) ≈ 37.68 cm.

Tags

CCSS.7.G.B.4

Front

How do you convert diameter to radius?

Back

Divide the diameter by 2.

Tags

CCSS.7.G.B.4

Front

What is the area of a circle with a radius of 7 cm?

Back

A = π(7)² ≈ 153.94 cm².

Tags

CCSS.7.G.B.4