We use the property that the angles of a triangle add up to 180 degrees.

Step 1:

Find the given angles

Step 2:

Subtract the given angles from 180 to get the missing angle.

Worksheets to find the missing angle in a triangle

Angles of Triangles Add Up To 180 Degrees

Ex: Could a triangle have the given angle measures?

a) 115, 35, 30

b) 45, 45, 60

Since all three angles add up to 180 degrees, you can find the missing angle by subtraction.

How to find a missing angle in a triangle

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