For any triangle, the sum of its interior angles will be equal to 180°
From there, we can make the next equation:
x + 51 + x + 73 + 72= 180
In this equation, I will simplify on the left, adding 51, 73 and 72.
2x + 196 = 180
Now I will subtract 196 on both sides.
2x = 180 - 196
2x = -16
Next, I will divide by 2 on both sides.
x = -16 / 2
x = -8
Now that I have the value of x, I can solve for A
A = x + 73
A = -8 + 73
A = 65°
