Find the probability of a dart landing in one of three plane figures in a rectangular board.
On a 12 by 20 rectangular board, three plane figures are drawn: a square 6 on a side , a circle with radius 4 and an equilateral triangle that is 8 on a side. If a dart is thrown that does hit the large rectangle what is the probabillity that it hits inside one of the three plane figures? (Landing on the side of a figure counts as being in the figure). Leave as a percent.