G) Angles on a straight line add to 180°; According to this rule, we can formulate the following equation: (2x + 4) + (x + 8) = 180 Now, just simplify and solve for x: 3x + 12 = 180 3x = 168 x = 56°
H) What is shown on the diagram are sometimes called C-angles; They also add to 180°; This C-angle rule is one of 3 that exist when you have a pair of parallel lines (in this case the two horizontal ones) and one line passing through them both. Using the C-angle rule, we can formulate the equation: (3x + 9) + (2x - 4) = 180 Simplify and solve: 5x + 5 = 180 5x = 175 x = 35°
