Circles Vocab Flashcard

Front

What is a central angle?

Back

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

Front

What is a secant line?

Back

A secant line is a line that intersects a circle at two points.

Front

What is a chord in a circle?

Back

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

Front

What is a radius of a circle?

Back

A radius is a line segment from the center of the circle to any point on the circle.

Front

What is the definition of a tangent angle?

Back

A tangent angle is an angle formed between a tangent line to a circle and a radius drawn to the point of tangency.

Front

What is the difference between a chord and a secant?

Back

A chord connects two points on the circle, while a secant intersects the circle at two points and extends beyond the circle.

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

What is 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

What is the diameter of a circle?

Back

The diameter is a line segment that passes through the center of the circle and has endpoints on the circle; it is twice the length of the radius.

Front

What is the relationship between the radius and diameter?

Back

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