Given: ∆ABC is isosceles m∠ACB = 120°, CM = 12 m∠BMC = 60° Find: AB

36

Step-by-step explanation:

As the triangle ABC is isosceles so A and B has the same measures

And, the sum of the angles is 180°.

Therefore 2 times the measure of angle

B plus  120° = 180°,

So, the equation:

2x + 120 = 180

So x = 30

Now we have to apply the law of sin on the triangle BMC as shown below:

Now calculate for BC

BC = 20.7

We use the law of sin again i.e

So AB is 36