Question

If the measure of angle 10 = 77 degrees, the measure of angle 7 = 47 degrees and the measure of angle 16 = 139 degrees, find the measure of each missing angle.

Answer 1

m< 18 = 139° ( vertical angles)

m<17 = 180° - 139° = 41° (angle on a straight line)

m<15 = 41° (vertical angles)

m<5 = m<15 = 41° (vertical interior angle)

m<7 + m<6 + m<5 = 180° (angle on a straight line

47° + m<6 + 41° = 180°

m<6 = 180° - 47° - 41° = 92°

m<12 + m<6 + m<15 = 180° (sum of interior angle of a triangle)

m<12 + 92° + 41° = 180°

m<12 = 180° - 92° - 41° = 47°

m<12 + m<11 + m<10 -