Name:_____________________________ Class:_______________

Lesson 5: Investigating Angles in a TriangleA triangle's three angles will ________________total up to _________ degrees!

Example 1:

Example 2: Find the measure of the third angle in each triangle.

a) A triangle with two angles measuring 110°and 45°

b) A triangle with one right angle and a 40° angle

c) A triangle with two angles measuring 60°

Interior Angles of Polygons

Name:_____________________________ Class:_______________

An Interior Angle is an angle ____________a shape.

Example 3: If we know one angle is 45° what is angle "a" ?

Angle a is... ________________________

Angles On One Side of A Straight LineAngles on one side of a straight line will _____________ add to ______ degrees. If a line is split into 2 and you know one angle you can always find the other one.

________________________________________

Example 4: What is angle "b" ?

Name:_____________________________ Class:_______________

Angle b is 180° _______________________of the other angles.Sum of known angles = ______________________________________ Sum of known angles = ______________________________Angle b = _____________________________Angle b = _______________________

Example 5:

Example 6: Find the missing angles x and y. Remember that ALL triangles add up to a total of 180 degrees!

Name:_____________________________ Class:_______________

Example 7: Find the missing angles a, b, c, d, e and f. Remember that ALL triangles add up to a total of 180 degrees!