Answer:
<B=119
Explanation:
Each line of the triangle is straight, meaning they add up to 180. Additionally, all the angles of the triangle add up to 180. Using that, you can find the measure of each angle.
For <C;
180-112=68
So <C=68
For <A;
180-51-68=61
So <A=61
To make sure that all these angles add up correctly;
51+68+61=180
For <B;
180-61=119
So <B=119