Unit Three: Measuring Circles Exam

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 formula for the area of a circle?

Back

A = πr², where A is the area and r is the radius.

Front

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

Back

Radius (r) is half of the diameter (d): r = d/2.

Front

What is the relationship between diameter and circumference?

Back

Circumference (C) is π times the diameter (d): C = πd.

Front

What is a composite figure?

Back

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

Front

How do you calculate the area of a composite figure?

Back

Find the area of each simple shape and then sum them up.

Front

What is the diameter of a circle?

Back

The diameter is the distance across the circle through its center, equal to twice the radius.

Front

What is the significance of π (pi) in circle measurements?

Back

π is a constant approximately equal to 3.14, used in formulas for circumference and area.

Front

If a circular pool has a diameter of 21 feet, what is its radius?

Back

The radius is 10.5 feet.

Front

What is the area of a circle with a radius of 5 inches?

Back

A = π(5)² = 25π ≈ 78.54 in².