having trouble with transforming geometric formulas

[keanuk]

i really dont know much about transforming geometric formulas, i really need a basic step through of how to do them

ill give you an example of one of my problems

V = lwh;h

 

[mmm4444bot]

Follow the rules of algebra; whatever you do to one side of an equation must be done to the other side as well.

V = l * w * h

Solve for h.

You want to get h by itself. Recognize that dividing the righthand side by l * w results in h by itself because the l and w in the numerator cancel with the l and w in the denominator.

V/(l * w) = (l * w * h)\(l * w)

V/(l * w) = h

If you would like more help in the future, then please post your work, and try to say something about why you're stuck.

Cheers,

~ Mark

 

[keanuk]

thank u. i was completely lost as it got taught over the days i was absent from school.

 

[keanuk]

okay so i should have asked for a breakdown of a harder problem and now i an unsure..

please help me figure out if what i am doing is correct or completely wrong

A=1/2h(b1+b2)
2HA=2/1h*1/2h(B1+B2)
2HA=b1+b2
2HA-B2=B1

i thin the 2HA is wrong..

 

[Mrspi]

okay so i should have asked for a breakdown of a harder problem and now i an unsure..

please help me figure out if what i am doing is correct or completely wrong

A=1/2h(b1+b2)
2HA=2/1h*1/2h(B1+B2)
2HA=b1+b2
2HA-B2=B1

i thin the 2HA is wrong..

Please don't change variables in "midstream"....be aware that H and h are NOT the same.

Also, I believe that some parentheses are necessary in your original problem to clarify just what's what.

A = (1/2)*h * (b1 + b2)........because this is the STANDARD formula for the area of a trapezoid, I'm quite confident that the parentheses should be around (1/2).


Now...another little difficulty....you did not say which variable you are supposed to solve for!

Assuming that you probably are asked to solve for either b1 or b2, I'd suggest this:

Multiply both sides of the equation by 2, to eliminate the (1/2) on the right side:

2*A = 2*(1/2)*h*(b1 + b2)

On the right, 2*(1/2) is just 1, so you'll have

2A = h * (b1 + b2)

Next, if you are solving for either b1 or b2, you want to eliminate the multiplication by h. Divide both sides by h:

(2A) / h = [h * (b1 + b2)] / h

(2A) / h = b1 + b2

Now...you should be able to finish it.