Question 255408
picture the 4m pole standing at the origin, running up the y-axis


the 12m pole is standing on the x-axis, A meters away


the slope of the line from the bottom of 4m to the top of 12m is 12/A
___ the y-intercept is 0
___ the equation is y = 12x / A


the slope of the line from the top of 4m to the bottom of 12m is -4/A
___ the y-intercept is 4
___ the equation is y = -4x / A + 4


to find the intersection ___ 12x / A = -4x / A + 4 ___ 16x / A = 4 ___ 16x = 4A ___ 4x = A


substituting ___ y = 12x / 4x = 3


the height of the intersection is 3m