First you have to find the area of the triangle. To do this you must us the formula 1/2 multiplied by the base and height of the triangle. In this case the equation would be: 1/2 (or 0.5) x 18 x 9 which equals 81. Then you would have to find the area of the square, which is base times height which would be: 18 x 18. This would equal 324. To get your final answer you need to find the product of the two areas which would equal 405.