PLEASE HELP I GIVE THANKS

7 is easy you just use the distance formula which is derived from the Pythagorean theorem √(x1-x2)^2 + (y1-y2)^2 so you take -2 - 6 = -8 and 8 - (-2)= 10 then you square both and add them  64 + 100= 164 then take the square root so 12.8
8 is more difficult  you have to use the Pythagorean theorem twice once to find eg then to find ag so to start you take 16^2 + 18^2= EG^2 so EG = 24.08 then you take 16^2 + 24.08^2 = 28.9^2 so the answer is c