Cirlces Circles Circles

Front

What is the definition of a circle?

Back

A circle is a set of points in a plane that are equidistant from a fixed point called the center.

Front

What is the formula for the circumference of a circle?

Back

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

Front

How do you calculate the radius from the diameter?

Back

The radius (r) is half of the diameter (d), so r = d/2.

Front

What is the relationship between radius and diameter?

Back

The diameter is twice the radius, so d = 2r.

Front

What is the formula for the area of a circle?

Back

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

Front

If a circle has a radius of 5 inches, what is its diameter?

Back

The diameter is 10 inches, since d = 2r.

Front

What is the circumference of a circle with a radius of 10 inches?

Back

The circumference is 20π inches, calculated using C = 2πr.

Front

What is the radius of a circle with a circumference of 12π inches?

Back

The radius is 6 inches, calculated using r = C/(2π).

Front

What is the diameter of a circle with an area of 50π square inches?

Back

The diameter is approximately 12.6 inches, calculated using d = 2√(A/π).

Front

What is a chord in a circle?

Back

A chord is a line segment whose endpoints lie on the circle.