Question

What is the value of x?answer key is showing that it is 120°

Answer 1

yes i got it the answer is 110

∠AOC=2×∠ADC∠AOC=2×∠ADC  

[Center angle is double of the major angle]

∠ADC=1402=70∘∠ADC=1402=70∘

∠ABC+∠ADC=180∘∠ABC+∠ADC=180∘

∠ABC+70∘=180∘∠ABC+70∘=180∘

∠ABC=110∘∠ABC=110∘

Answer 2

See attachement

Find ∠AOC (reflect angle):

Angle at a point is 360º

∠AOC = 360 - 140 = 220º

Find ∠ABC:

Angle at the centre is twice the angle at the circumference

∠ABC = 220 ÷ 2 = 110º

Answer: (a) 110º