Skip to lesson

Choose “Save as PDF” in the print dialog to keep a copy.

Cogito

Integrated Math 2 · Chapter 7 · Lesson 2

Practice Worksheet

Angle and Triangle Theorems

The results a proof is built from.

12 problems · about 21 minutes · G-CO.C.9, G-CO.C.10

NameDate

Figure — use these to answer the problems

Set an angle and picture its supplement. The two must total 180°.
0306090120150180110°
Angle in degrees110
Figure 1

Warm Up

Straightforward practice. Get the method working first.

5 problems

  1. A triangle has angles 80° and 55°. What is the third, in degrees?

    Answer

  2. What does an exterior angle equal?

    • The sum of the two opposite interior angles.
    • The adjacent interior angle.

  3. An angle is 35°. Its complement, in degrees?

    Answer

  4. An angle is 140°. Its supplement, in degrees?

    Answer

  5. A triangle has angles 90° and 35°. The third, in degrees?

    Answer

Build It Up

The same ideas with more to keep track of.

3 problems

  1. Interior angles 45° and 65°. The exterior angle at the third vertex, in degrees?

    Answer

  2. One vertical angle is 72°. What is the other, in degrees?

    Answer

  3. An isosceles triangle has an apex angle of 40°. Each base angle, in degrees?

    Answer

Stretch Yourself

Mixed problems. Work out what kind of question it is before you start.

4 problems

  1. Sort each angle pair by whether they are equal or supplementary.

    Write each item under the heading it belongs to: Vertical angles · Corresponding angles on parallel lines · Co-interior angles on parallel lines · Angles on a straight line

    Equal

    Supplementary

  2. A triangle has two angles of 60°. The third, in degrees?

    Answer

  3. The Third Angle

    A triangle has angles 50° and 60°. What is the third, in degrees?

    Answerdegrees

  4. The Supplement

    An angle is 110°. What is its supplement, in degrees?

    Answerdegrees