Circumference of Circles and Perimeter of Composite Shapes

Front

What is the formula for the circumference of a circle?

Back

C = 2πr, where C is the circumference and r is the radius.

Front

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

Back

C = 2π(5) = 31.4 meters.

Front

What is the relationship between diameter and radius?

Back

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

Front

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

Back

r = C / (2π).

Front

What is the circumference of a circle with a radius of 12.5 mm?

Back

C = 2π(12.5) = 78.54 mm.

Front

What is the perimeter of a rectangle with length 10 m and width 5 m?

Back

P = 2(l + w) = 2(10 + 5) = 30 m.

Front

What is a composite shape?

Back

A composite shape is made up of two or more simple shapes.

Front

How do you calculate the perimeter of a composite shape?

Back

Add the lengths of all the outer sides.

Front

If a circular garden has a circumference of 393 ft, what is its radius?

Back

r = C / (2π) = 393 / (2π) ≈ 62.5 ft.

Front

What is the circumference of a circle with a radius of 9 meters?

Back

C = 2π(9) = 56.52 meters.