Two walls on a city collapsed. The only solution found was attaching two ropes on each wall to hold each other, as in the image above. Knowing that the walls have 9 and 3 meters, find the height of the point which the two ropes cross.
Let the distance between the walls be l
One rope goes from y = 9 to 0 in length l now let's also make l = 1 for convenience
equation y = -9/2x +9
other rope goes from 0 to 3 in lenght l (which is 1)
equation y = 3/2 x
set them equal to find 'x' 3x = -9x+9
12x = 9
x = 3/4
now find the height by puttin 'x' into one of the equations y = 3x = 3 * 3/4 = 9/4 meters high at cross