area = bh / 2
Since you already know the area and height, the equation becomes:
150 = b(20) / 2
divide 150 by 20:
7.5
Now, multiply 7.5 by 2:
15
Now the equation is:
150 = (15)(20)/2
You can check your work by multiplying 15 by 20 and dividing the answer by 2 to insure that you get 150:
15 * 20 / 2 = 150
Your answer would be:
C. 15 cm
