Question

13 In the figure O is the centre of the circle. And triangle ADB=120°, triangle OAC=30° , Then
Find triangle ACB
Find triangle OAB
Justify that ABC is an equilateral Triangle..

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Answer 1

Answer:

angleACB=60( half of angleADB)

angle AOB=120(twice of angle ACB)

angle OAB=30(OAB=OBA)

angle CAB=60(30+30)

angle CBA=60180-120)

hence it is an equilateral triangle.