The sum total of the angles in a triangle is equal to 180° degrees.
I'm assuming the question looks like this?

If so then the answer should be:

Hope this helps!
Answer:
Slope (m) = 
Step-by-step explanation:

X = 4 – 1 = 3
Y = 4 – 2 = 2

Equation of the line:
y = 0.66666666666667x + 1.3333333333333
or

When x=0, y = 1.3333333333333
When y=0, x = -2