Question

The vertices of ∆ABC are A(-2, 2), B(6, 2), and C(0, 8). What is the perimeter of ∆ABC in units?

Answer 1

Ok here what you need to use is the distance formula. So the process should look like this:
L(AB) = √[(6 - -2)² + (2 - 2)²] = 8
L(BC) = √[(0 - 6)² + (8 - 2)²] = 8.4853
L(AC) = √[(0 - -2)² + (8 - 2)²] = 6.3246

8 + 8.4853 + 6.3246 = 14.8099
I hope this is what you were looking for.