The sum of all the internal Angles in a triangle is: Angles in Triangles The sum of all the internal Angles in a triangle is: How can we find the value of the other 2 angles in the triangle? 180º = the sum of angle 1 + angle 2 + angle 3 180º = 90º + angle 2 + angle 3 Are angle 2 and angle 3 the same or different? Since angle 1 is 90º, angle 2 and angle 3 must combine to give us 90º because the internal angles of a triangle add up to 180º!! Therefore, angle 2 and angle 3 are both half of 90º 2 180º 1 3 How much is this angle?

What kind of triangle is this? What is the total sum of all the internal angles of this triangle? How could you find the value of each Internal angle? 180º = 3a 3 60º = a Therefore, all internal angles for this triangle are 60º! 180º = angle1 + angle2 + angle 3 180º = ___ + ___ + ___ If all three angles are the same, then couldn’t we create an expression to help us solve the problem? Let a represent the internal angles 180º = a + a + a