Unit 10 Test Review: Circles

Which of the following is the name of a CHORD in the diagram?

• ED

• AB

• CA

• EB

Answer explanation

A CHORD is a line segment with both endpoints on the circumference of a circle.

Which of the following is the name of a TANGENT in the diagram?

• CA

• ED

• line t

• EB

Answer explanation

A TANGENT is a line, segment, or ray that intercepts a circle only once (at the "point of tangency").

Which of the following is the name of a RADIUS in the diagram?

• CA

• ED

• AB

• EB

Answer explanation

A RADIUS is a line segment with one endpoint on the center of the circle and the other endpoint on the circumference of the circle.

Which of the following is the name of a SECANT in the diagram?

• CA

• AB

• EB

Answer explanation

A SECANT is a line that intercepts a circle twice.

Which of the following is the name of a DIAMETER in the diagram?

• CA

• AB

• EB

Answer explanation

A DIAMETER is a line segment that goes through the center of a circle and has both endpoints on the circumference of the circle.

The circle has diameter AB. Find x.

Answer explanation

A diameter cuts a circle in half, into two semicircles. One semicircles measures exactly 180°.

m∠BCO = ____ °

Answer explanation

A tangent line is always perpendicular to the radius of the circle.

If two lines are perpendicular, they create 90° angles.

Length of AB = ____

• 16

• 8

• 16√3

• 3

Answer explanation

Remember, when a triangle has angles of 30°-60°-90°, there are rules that help you find the length of each side of the triangle.

They are from "Special Triangles" lessons in your notebook.

x =

• 6

• 4

• 5

• 4.5

Answer explanation

Find "Tangent Theorems" in your notes to help you with this question.

Find the perimeter of the quadrilateral.

Answer explanation

Use "Tangent Theorems" to find the lengths of the missing line segments.