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.