The trapezoid is a quadrilateral with one pair of parallel sides. 

The parallel sides of a trapezoid are called the bases, symbolized by b1 and b2 (smaller base = b1, bigger base = b2) 

The height of the trapezoid is the perpendicular distance between the bases, symbolized by h. 

The area of the trapezoid is equal to the average of the bases times the height. So, you add the two bases, divide by 2, and then multiply by the height. This would be: 

area = ((b1 + b2) / 2)h 

to find the height, you isolate h 

[(2×area)/(b1+b2)] = h

So [(2×150)/(74)] = h
300/74 = h
h = 4.05405....
hey, same answer! only in our class its base 1 plus base 2 times height divided by two.
but it still gives the same answer!
So lets see...
area equals base one plus base two times height divided by two so 150 times two...well thats 300 then fourteen plus 60 so thats 74. 300 dvided by 74 gives us 4.054054054054... so the answer!