I am trying to the points of my rectangle land on both my projection and my drop construction lines.
When I use the rotate tool and make the point hit my projection line, it also changes my drop (height)
and I miss my measurement. My top point (left side) needs to stay constrained, I am rotating from there. My friend uses onshape and can have a constraint at his top point so that he can alter his bottom points to hit both projection and drop lines.

I will include a photo of what I am trying to do thank you.

Red box is me eyeballing it and getting it āclose enoughā but I have outlined a red triangle where I have gone over my drop length. Is there any way to do what I am asking, right now it takes awhile of guessing and checking. Thanks

Iām not quite sure I understand correctly: Are you basically trying to rotate a rectangle from the top left corner until the bottom right corner meets a line?

To clarify, in this example I need to be constrained to that top left point, then my rectangle corners on the bottom right need to hit a line at 48" projection and 36" drop (height)

Iām always afraid to swing arcs in SketchUp because it doesnāt represent them well. Personally, I rely on other software when I need to solve such problems like this one.

I suspect you may have too many constraints such that you can either hit one line or the other but not both, unless thereās some other variable to play with.

No need to. Examples like this one are easily solved with the āArc Pieā tool. As demonstrated above by @mihai.s, and accurate.
You are right about there being too many constrains. The bottem line is enough.

In that case the rectangle has not a fixed length. You might have stated that in your first post. My bad.
But still, you canāt have both. Only in exceptional cases.

Look at your last posted image. Either the rectangle needs to be wider to reach the vertical line, or the vertical line you want its upper corner to reach needs to move a little to the left.

It cannot move left, and the rectangle cannot become wider considering this is a constraint. The rectangle can become longer horizontally though. It has real world constraints. I do not have the correct angle to make the two lines hit my constraints

The item on the left is where I have eye balled it and you can see how it should look, although it takes a lot of time messing with rotating the rectangle. The rectangle can become as long as needed to hit my construction lines

These corners need to hit the blue lines while maintaining the 1.5" width of my rectangle and constraint point at the top left. The rectangle can become as long as needed.

I once wrote an extension to handle this kind of problem. Never published it though. Iām not home now, but later Iāll look and see if I can find it.