Circumference and Area of Circles

Front

What is the formula for calculating the circumference of a circle?

Back

The circumference (C) of a circle can be calculated using the formula C = πd, where d is the diameter, or C = 2πr, where r is the radius.

Tags

CCSS.7.G.B.4

Front

What is the value of π (pi) to two decimal places?

Back

The value of π (pi) to two decimal places is approximately 3.14.

Tags

CCSS.HSG.GMD.A.1

Front

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

Back

The radius (r) of a circle is half of the diameter (d). Therefore, if the diameter is 10 cm, the radius is 5 cm.

Tags

CCSS.7.G.B.4

Front

How do you convert diameter to radius?

Back

To convert diameter to radius, divide the diameter by 2.

Tags

CCSS.7.G.B.4

Front

What is the formula for calculating the area of a circle?

Back

The area (A) of a circle can be calculated using the formula A = πr², where r is the radius.

Tags

CCSS.7.G.B.4

Front

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

Back

Using the formula A = πr², the area is A = π(7)² = 49π ≈ 153.94 m².

Tags

CCSS.7.G.B.4

Front

What is the relationship between diameter and circumference?

Back

The circumference of a circle is directly proportional to its diameter, expressed as C = πd.

Tags

CCSS.7.G.B.4

Front

How do you find the circumference if you only have the radius?

Back

If you have the radius (r), you can find the circumference using the formula C = 2πr.

Tags

CCSS.7.G.B.4

Front

What is the circumference of a circle with a radius of 3 inches?

Back

Using the formula C = 2πr, the circumference is C = 2π(3) ≈ 18.85 inches.

Tags

CCSS.7.G.B.4

Front

What is the diameter of a circle with a circumference of 31.4 cm?

Back

To find the diameter from the circumference, use the formula d = C/π. Therefore, d = 31.4/π ≈ 10 cm.

Tags

CCSS.7.G.B.4