for this we will use pythagoras theorem to find the distance we need to find the first two sides by finding the distance between the corresponding sides for -7 and 2 the difference is 9 and for -5 and 3 the distance is 8 pythagoras thereom is a^2+b^2=c^2 so 9^2+8^2=x^2 81+64=x^2 145=x^2 x=12.04159... x=12.042 (3dp)