Segment Lengths in 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 diameter of a circle?

Back

The diameter is the longest distance across the circle, passing through the center, and is twice the radius.

Front

What is the radius of a circle?

Back

The radius is the distance from the center of the circle to any point on its circumference.

Front

What is a tangent to a circle?

Back

A tangent is a line that touches the circle at exactly one point and is perpendicular to the radius at that point.

Front

How do you find the length of a segment that is tangent to a circle?

Back

Use the Pythagorean theorem: if a tangent segment and a radius form a right triangle, the length of the tangent can be found using the formula: tangent^2 = hypotenuse^2 - radius^2.

Front

What is the formula for the circumference of a circle?

Back

The circumference C of a circle is given by the formula C = πd, where d is the diameter.

Front

What is the area of a circle?

Back

The area A of a circle is given by the formula A = πr^2, where r is the radius.

Front

What is the relationship between the radius and diameter?

Back

The diameter is twice the radius: d = 2r.

Front

What is a chord in a circle?

Back

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

Front

What is the central angle of a circle?

Back

A central angle is an angle whose vertex is at the center of the circle and whose sides are radii.