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.

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