Question

Find the interior angles of ABC where A (2,-3), B (4,2) and C (-5,-2)
Please, help

Answer 1

Methodology, please. Vectors?

Answer 2

geometry only

Answer 3

I confuse when the definition to find the angle is, let me post the pic

Answer 4

Here is my work for the first angle, but I got confuse when the third one is negative when we don't have the absolute value on the arctan formula

Answer 5

WHEN ANGLE IS NEGATIVE,IT IS OBTUSE
BECAUSE IN SECOND QUADRANT TAN IS NEGATIVE.

Answer 6

Then?

Answer 7

But you can't say that since if the angle lie on quadrant 2 or 4 and it is acute still. How can we argue? like