Lesson on Triangles Sum Theorem and Exterior Angle Theorem

The Triangle Sum Theorem states that the sum of all angles in a triangle is ______. 

• 45°
• 90°
• 180°
• 360°

Find the measure of the angle indicated. 

• 139°
• 66°
• 138°
• 116°

What is the third angle of a triangle whose 1st angle is 79 and the 2nd angle is 43?

• 43
• 58
• 72
• 101

Find the measure of the missing angle.

• 90^o
• 10⁰
• 130^o
• 50^o

Solve for x.

• 16
• 11
• 50
• 6

If all three angles are exactly the same measure, how big is each angle?
Hint:    x + x + x  = 180

• 180 degrees
• 90 degrees
• 50 degrees
• 60 degrees

Angles that are exactly 90 degrees are called _____ ______.

• tight angles
• acute angles
• obtuse angles
• right angles

If 2 of the angles of a triangle are 30 and 70 degrees, the third angle measures...

• 80
• 100
• 60
• 90

Find the measure of the indicated angle. 

• 26
• 36
• 85
• 144

Solve for x.

• 71
• -3
• 35
• -19