Question 159043
the easiest solution is semi-graphical


picture the 80 foot pole standing on the origin and going up the y-axis


the 20 foot pole is standing on the x-axis, 100 feet from the origin


y=mx+b


the equation of the line from the top of 80 to the bottom of 20 is y=-.8x+80


the equation of the line from the bottom of 80 to the top of 20 is y=.2x


substituting __ .2x=-.8x+80 __ adding .8x __ x=80


substituting __ y=.2(80) __ y=16