A + C (-5, -7) is 7 units to the left of point H (-7, 7) is more than 7 units up and left of point H the x axis is at (infinity, 0), being only 7 points up from point H
Set up a proportion: 3/10= x/80. Then if you multiply 10 by 8, you get 80 on both sides, But, If you do it to the top, you also have to do it to the bottom, so the anser is 3 x 8 , or 24.