In a triangle all of the angles always add up to 180, so let's set up an equation.
79 + 37 + y = 180
Simplify
116 + y = 180
Subtract 116 from both sides.
y = 64
The value of y is 64.
Hopefully this helps! If you have any more questions or don't understand, please comment or DM me, and I'll get back to you ASAP. :)