I need to make a the subject of the equation A 12abh it is

I need to make a the subject of the equation

A = 1/2(a+b)h

it is the formula for the area of a trapezium where a and b are parallel and h is distance between them.

Solution

A=(1/2)(a+b)h, given.

To make a the subject of the equation means a is expressed in terms of the area, Aone of the parallel sides, b and the distance btween the parallel sides or the height ,h of the trapezeum.

Multiply both sides of the given equation by 2:

2A=(a+b)h .

Now divide the both sides of this equation by h:

2A/h=a+b

Subtract b from both sides:

2A/h - b = a.

This is the same equation as below

a=2A/h - b.

This could be writen like:

a=(2A-hb)h.

The equation could be used to find one of the pair of parallel sides of the trapezeum, when its other side, area and the the height (= distance between the parallel lines) are given.

Hope this helps.