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

What is the value of π (pi) commonly approximated as?

Back

π is commonly approximated as 3.14.

Front

How do you calculate the circumference of a circle with a diameter?

Back

C = πd, where d is the diameter.

Front

What is the relationship between radius and diameter?

Back

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

Front

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

Back

C = 2π(10) = 62.8 cm.

Front

What is the perimeter of a semicircle?

Back

P = πr + d, where d is the diameter.

Front

How do you find the perimeter of a composite shape?

Back

Add the lengths of all the outer sides of the shape.

Front

What is the circumference of a circle with a radius of 5 m?

Back

C = 2π(5) = 31.4 m.

Front

If a semicircle has a radius of 4 m, what is its perimeter?

Back

P = π(4) + 8 = 12.56 + 8 = 20.56 m.

Front

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

Back

C = 2π(12.5) = 78.54 mm.