In a trapezium ABCD, AB || CD and ∠BCD = 50°. If angle bisectors of ∠BCD and ∠ADC meet at point O and ∠COD = 115°, then what is the measure of ∠BAD?

In a trapezium ABCD, AB || CD and ∠BCD = 50°. If angle bisectors of ∠BCD and ∠ADC meet at point O and ∠COD = 115°, then what is the measure of ∠BAD? Correct Answer 100°

∠ABC = 180° – 50° = 130°

∠OCD = 50°/2 = 25°

Let ∠ODC = x

In ∆BOD

∠OCD + ∠ODC + ∠COD = 180°

25° + x + 115° = 180°

x = 40°

∠ADC = 2x = 80°

∠ADC = Exterior ∠A = 80°

∠BAD = 180° – 80°

∠BAD = 100°

Related Questions

How far is point 'R' from Point 'T'? Statement (I): Point 'R' is 5 metres to the north of point 'M'. Point 'U' is 4 metres to the east of point 'R'. Point 'T' is to the west of point 'R' such that points 'U' 'R' and 'T' form a straight line of  metres. Statement (II): Point 'Z' is metres to the south of point 'T'. Point 'U' is  metres to the east of point 'T'. Point 'M' is  metres to the east of point 'Z'. Point 'R' is  metres to the north of point 'M'. Point 'R' lies on the line formed by joining points 'T' and 'U'.