"Keith Nuttle" wrote

| | The basic formula is a simple direct proportions calculation
| |
| | X1 X2
| | ------ = ------
| | Y1 Y2
| |
| |
| | Which is calculated as
| | X1 * Y2 = Y2 * X2
| |
|
| X3?
|
|
| Would you believe X2
|
|
Ah. I still don't see the answer here, though.
You have:

X1 * Y2
------- = Y2
X2

But Y2 is on both sides. So I tried putting Y1
on the left, thinking maybe you intended that.
But that doesn't work either. I thought maybe
there's an easier method than mine. I'm not
a math whiz. But so far we don't seem to have
a 1-step solution.