Stefan is measuring the angles of a triangle. He measures the first angle and gets a measure of 80° What does he know for sure about the other two angles?

Answer 1

The sum of the angles in a triangle is always 180°. Therefore, if Stefan measures one angle to be 80°, the sum of the other two angles must be 100° in order to add up to a total of 180°. However, he does not know for sure what the individual measures of the other two angles are.