Basic Triangle Facts

• A triangle is a polygon with 3 straight sides coming to 3 points.

• The sum of the interior (inside) angles of a triangle is 180 degrees.

• Triangles can be classified by their angles and sides.

Classification of Triangles by their
SIDES & ANGLES

How to Find the Missing Angle in a Triangle

• Since all the the interior angles of a triangle add up to 180 degrees, we can find a missing angle if we know the measurement of 2 other angles.

• Simply add together the two angles you know, and subtract that value from 180 to find the missing angle.