Area and Circumference of Circles

Front

What is the formula for finding the circumference of a circle?

Back

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

Front

What is the radius of a circle?

Back

The radius is the measurement from the center of a circle to an edge of the circle.

Front

What is the diameter of a circle?

Back

The diameter is the measurement from one edge of the circle to the opposite edge, passing through the center.

Front

How do you calculate the area of a circle?

Back

A = π * r², where A is the area and r is the radius.

Front

If a circle has a radius of 5 mm, what is its circumference?

Back

C = 2 * π * 5 = 10π or about 31.42 mm.

Front

What is π (pi)?

Back

π (pi) is a mathematical constant approximately equal to 3.14, representing the ratio of the circumference of a circle to its diameter.

Front

What is the relationship between radius and diameter?

Back

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

Front

If the circumference of a circle is 31.4 mm, what is the radius?

Back

r = C / (2 * π) = 31.4 / (2 * π) = 5 mm.

Front

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

Back

C = 2 * π * 12.5 = 25π or about 78.54 mm.

Front

What does it mean if a line is a radius of a circle?

Back

It means the line connects the center of the circle to any point on the circle.