angle 2 and angle 99 are vertically opposite angles. Vertically opposite angles are equal. This means that
angle 2 = 99 degrees
angle 1 and angle 99 are linear pairs. This means that their sum is 180 degrees. Thus,
angle 1 + 99 = 180
angle 1 = 180 - 99
angle 1 = 81 degrees
angle 3 = angle 1 because they are vertically opposite
angle 3 = 81 degrees
Line a and b are parallel and line t is the transversal. angle 1 and angle 5 are corresponding angles because they have similar position and lie on the same side of the transversal. Corresponding angles are equal. Thus,
angle 5 = angle 1
angle 5 = 81 degrees
angle 2 and angle 6 are corresponding angles
angle 2 = angle 6
angle 6 = 99 degrees
angle 2 and angle 4 are alternate interior angles. they lie on alternate sides of the transversal. alternate angles are equal. Thus,
angle 2 = angle 4
angle 4 = 99 degrees
angle 7 and angle 6 are linear pairs. thus
angle 7 = 180 - angle 6 = 180 - 99
angle 7 = 81 degrees
