Geometric Ratio Pipe Problem: How to Find D2/D1?

[xzibition8612]

Homework Statement

Find D2/D1.
See attachment.

Homework Equations

The Attempt at a Solution

Ans: D2/D1 = 0.68

I can't figure this one out. Any special trigonometric identities that might help here? Thanks.

 

[Fredrik]

Draw two more lines to/from the point where the upper diagonal line intersects the lower horisontal line. One of them should be vertical. The other perpendicular to the diagonal lines. Now you have a rectangle and a bunch of right triangles to work with. Figure out all the other angles and draw them into your diagram.

One of the right triangles will have an edge of length D2. Use that to find the lengths of the other sides in units of D2. Keep doing that sort of thing until you have the length of D1 in units of D2.