Maths Question?

[bk T]

Young fellows, your young brains are needed to solve this Maths question:
Here it goes:

Area of Trapezium = (6ah²+9a) square units
Perpendicular ht = (4h²+b) units
Express the sum of lengths of the parallel sides in terms of " a ".
Thanks

[SP8's]

http://www.mathsteacher.com.au/year8..._trap/trap.htm Google is your friend ...

[Terry Porritt]

http://www.mathsteacher.com.au/year8..._trap/trap.htm Google is your friend ...

That is not what bk T is asking.

At first sight the problem seems unsolvable since there are 3 undefined variables a, h, b and only one equation; - the area expressed in terms of the sum of the parallel sides and the perpendicular height. Thus it does not appear possible to express the sum of the parallel sides only in terms of 'a'.

Edit: it cannot be assumed that a, b, h are dimensions of the trapezium (trapezoid for American readers)

[roddy_boy]

How did you get on bk T?

[Jeff]

This may help.

http://en.wikipedia.org/wiki/Trapezoid

[Terry Porritt]

This may help.

http://en.wikipedia.org/wiki/Trapezoid

Like SP8's I'm afraid you haven't read the question posed. "We" all know the formulae for trapeziums/trapezoids, well at least you would if you went to school, that is............

Edit: as an aside the terms a, b, h in bk T's conundrum cannot be dimensional lengths associated with the trapezezium, those letters have been used to confuse the issue.

They are not lengths because his equations would not have dimensional homogeneity, and would become invalid.

For example you cannot add millimetres to square millimetres or millimetres cubed

[Jeff]

How do we know it is not his homework?

You should be able to calculate the sum of the lenghts with the equations supplied.

How can this person learn if we do the work for them.

[Terry Porritt]

The conundrum reworded is: get the sum of the lengths of the parallel sides from the equations given, by eliminating b and h and expressing the result only in terms of a.

Edit again: I think bk T is maybe a little too old to be doing school homework

[kahawai chaser]

I'm sure this is only 4th form maths, if I recall, long ago. Using simultaneous equations or similar for multiple variables. You input the above formulas into the standard trapezium formula, cross multiple, add-subtract, substitute, balance out, etc, to try resolve. There is a specific sequence, I think, for solving such equations.

[roddy_boy]

Except there are too many variables and not enough equations as Terry mentioned once or twice...

I feel bk T missed some info here, and won't be able to solve this without it.