Area/Circumference II

Front

What is the formula for the circumference of a circle?

Back

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

Front

How do you calculate the area of a circle?

Back

Area = r²π, where r is the radius.

Front

If the radius of a circle is 8 inches, what is the circumference using π = 3.14?

Back

Circumference = 2πr = 2 * 3.14 * 8 = 50.24 inches.

Front

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

Back

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

Front

If a circle has a circumference of 37.68 feet, how do you find the diameter?

Back

Use the formula d = Circumference / π. So, d = 37.68 / 3.14 = 12 feet.

Front

What is the area of a circle with a radius of 4 mm?

Back

Area = r²π = 4² * 3.14 = 16 * 3.14 = 50.24 mm².

Front

How do you convert diameter to radius?

Back

Radius = Diameter / 2.

Front

What is the approximate area of a circle with a diameter of 20 inches?

Back

First, find the radius: r = 20 / 2 = 10 inches. Then, Area = r²π = 10² * 3.14 = 314 in².

Front

What is the value of π used in these calculations?

Back

π is approximately 3.14.

Front

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

Back

Use the formula Circumference = 2πr.