Two vertices of an obtuse triangle are (6,4) and (0,0). The third vertex is located on the negative branch of the x-axis. What are the coordinates of the third vertex if the area of the triangle is 80 square units?
The height of the triangle is the y coordinate of (6,4) = 4
So
80 = (1/2) base * height
80 =(1/2) base * 4
80 = 2 * base
80/2 = base = 40 = distance from (0,0) to the third vertex
The third vertex is (-40 , 0)
