Circumference and Area of a Circle

Front

What is the formula for the circumference of a circle?

Back

The circumference (C) of a circle is calculated using the formula C = 2πr, where r is the radius of the circle.

Front

What is the formula for the area of a circle?

Back

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

Front

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

Back

Using the formula C = 2πr, the circumference is C = 2π(5) ≈ 31.42 m.

Front

If the radius of a circle is 10 in, what is its area?

Back

Using the formula A = πr², the area is A = π(10)² ≈ 314.16 in².

Front

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

Back

The diameter (d) of a circle is twice the radius (r), so d = 2r.

Front

How do you convert the circumference from meters to yards?

Back

To convert meters to yards, multiply the length in meters by 1.09361.

Front

What is the circumference of a circle with a diameter of 8 m?

Back

Using the formula C = πd, the circumference is C = π(8) ≈ 25.13 m.

Front

If a circle has an area of 50.24 m², what is its radius?

Back

To find the radius, use the area formula A = πr². Rearranging gives r = √(A/π). For A = 50.24 m², r ≈ 4 m.

Front

What is the value of π (pi) approximately?

Back

The value of π (pi) is approximately 3.14.

Front

How do you find the area of a circle if you know the circumference?

Back

First, find the radius using the circumference formula C = 2πr, then use A = πr² to find the area.