## Tuesday, May 31, 2016

### Daily Regents: Literal Equations (August 2014)

I'll be reviewing a New York State Regents Exam Question every day from now until the Regents exams begin next month. At least, that is the plan.

### August 2014, Questions 34

34. The formula for the area of a trapezoid is A = (1/2)h(b1 + b2).Express b1 in terms of A, h, and b2.

The area of a trapezoid is 60 square feet, its height is 6 ft, and one base is 12 ft. Find the number of feet in the other base.

You want to isolate the variable we want to solve for, in this case b1:

A = (1/2)h(b1 + b2)
Multiply by 2: 2A = h(b1 + b2)
Divide by h: 2A/h = b1 + b2
Subtract b2 from both sides: (2A/h) - b2 = b1
b1 = (2A/h) - b2

To find the answer to the second part, substitute the values you have into the equation you just created, and evaluate.

b1 = (2A/h) - b2 = (2(60)/6) - 12 = 120/6 - 12 = 20 - 12 = 8
The other base is 8 ft.

Any questions?

If anyone in Brooklyn is looking for an Algebra or Geometry Regents Prep tutor, send me a note. I have a couple of weekly spots available between now and June.