Illustrator: Rotate one object to align another object

Question

Situation

I need to match the red rectangle to the black lines.

Problem

I need to rotate the red rectangle at the same angle as the black lines.

Question

How can I adapt to the way the automatic way align objects to each other. Is there a way to get around this?

Answer 1

1. Select square
2. Activate direct select tool (a, white arrow, no this will not work with the black arrow*)
3. move mouse to one of the corner points of the square.
4. Once you snap to corner (be sure you have smart guides on) drag that corner so its on the line. (you may need to hold control down a bit depending on if the box is above or below the line)
5. Activate rotate tool (r)
6. Click on the corner, this moves the pivot there.
7. Move to oppsite corner and drag untill your cursor snaps to line.
8. Move back.

Animation 1: Screen capture of procedure above.

Alternate method draw a new line on top of the line with line tool. Alt click with line tool to get the angle. Rotate your grid to that angle. Redraw square.

* In general if you do not use the white arrow then you will have a very hard time doing a really big part of all that Illustrator does.