18.) The area of one of the triangles would be half of the area of the parallelogram, because the two triangles are congruent.
20.) The formula for the area of a parallelogram is:
A = b • h
110.5 = 13h
110.5 / 13 = 8.5
110.5 = 13 • 8.5
And because this is a measurement of the height, not the area, it is just meters (m)
So, the full answer is 8.5 m
I hope this helps!