SOLUTION: This is off of a worksheet and not a book. Problem states: A pair of telephone poles is supported by two cables. A cable line runs from the top of each pole to the bottom of t

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: This is off of a worksheet and not a book. Problem states: A pair of telephone poles is supported by two cables. A cable line runs from the top of each pole to the bottom of t      Log On


   

Question 127405: This is off of a worksheet and not a book.
Problem states: A pair of telephone poles is supported by two cables. A cable line runs from the top of each pole to the bottom of the other. If one pole is 20m high and the other pole is 30 m high, how high above the ground do the cables intersect?
Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
imagine the poles are 10m apart __ the distance is not important
__ but you want a number to make calculating the slopes easy

picture the 20m pole lying on the positive y-axis with the base at the origin
__ the 30m pole is 10m to the right with the base on the x-axis

the equation of one wire is y=-2x+20 __ the other wire is y=3x

solving simultaneously __ 3x=-2x+20 __ 5x=20 __ x=4

substituting __ y=3(4)