<span>180 degrese or some thing flat</span>
The fourth vertex would be at point (-9,1).
The slope from (5,-4) to (3,4) is -8/2 or -4.
So I did that with (-7,-7) to the fourth vertex to get the answer.
So we just need to plug in our values and solve

we are given v is 369 so we have

now we solve for x.
divide both sides by 20
square both sides
subtract 273 from both sides

so a temp of about 67 degrees C