Plot and connect the points a(2,3), b(2,-5), c(-4,-3), and find the area of the triangle it forms.

Check the picture below.

so we can simply split the triangular area into two smaller triangles, notice their base and height.

so, simply, get the area of each triangle, sum them up, and that's the area of the triangular section.

The answer is: a = about 63.59ft2 for 15