Lines and Centers of Circles

The length of the external common tangent is 15 units. If the radii of the two circles A and Z are 6 units and 12 units, respectively, find the distance between the centers of the two circles.

• 12

Find CE if BE = 10 and AC = 20.

• 4

• 5

• 6

• 7

What do you called the point of intersection between the circle and a tangent line?

• Point of Reference

• Point of Sale

• Point of View

• Point of Tangency

Which statement is true?

What is the relationship between circles a and b?

• They are different sizes.

• They are congruent.

• They are tangent.

• They are concentric.

Which line is constructed last in the instructions?

• Line g

• Line j

• Line i

• Line h

Why segments AB and AC have the same length?

• Segments AB and AC are equal because they are both diameters of the same circle.

• Segments AB and AC are equal because they are both chords of different circles.

• Segments AB and AC are equal because they are both tangents to the same circle.

• Segments AB and AC are equal because they are both radii of the same circle.

Which statements are true about the diagram with centers A and B?

• The length AB is equal to the length CD.

• Segment AM is perpendicular to segment BM.

• Point M is the midpoint of segment AB.

• Line CD is perpendicular to segment AB.

Which statement is true about the diagram with centers A and C?

• BC = CD

• AB = BC

• AB = BD

• BD = CD

The diagram was constructed with straightedge and compass tools. Which two segments have the same length as segment AC?

• AB

• CB

• CE

• BE