Hello from MrBillDoesMath!
Answer:
27
Discussion:
By the distance formula (or Pythagorean theorem)
distance = sqrt ( (change in x)^2 + (change in y)^2)
In our case this becomes
distance = sqrt ( (18 - (-9) )^2 + (-12 - ( -12))^2)
= sqrt ( ( 18 + 9) ^2 + ( -12 + 12) ^ 2)
= sqrt ( ( 18 + 9) ^2 + 0^2 )
= sqrt ( 27^2)
= 27
Geometrically, as both y coordinates = -12, the points define a horizontal line segment. The length is then simply the difference of the x coordinates, 18 - (-9) = 18 +9 = 27. Same answer as before
Thank you,
MrB