Figuring out angles

[Bsxed]

Trying to build a desk. Have all the standard measurements but having issues figuring out what the angles I need for the support beams I have attached a drawing the blue circles are the angles that I need to figure out. Also I need to know how long my beam has to be before being cut(green line). I don't just want the answer, although it will be appreciated but I also want to know how to solve this problem in the future. Thanks in advance for all your help.

 

[tkhunny]

Two Questions:

1) Are you using standard 2x4s? It's important to note that they aren't really 2" x 4".

2) Your horizontal members are not sufficiently labeled. Are they the same size as the diagonal members?

 

[Bsxed]

Two Questions:

1) Are you using standard 2x4s? It's important to note that they aren't really 2" x 4".

2) Your horizontal members are not sufficiently labeled. Are they the same size as the diagonal members?

Standard 2x4s and there are no horizontal members just the diagonal I just added the one on the left to show that the desks height will be 26 inches when completed. Thanks for the reply.

 

[tkhunny]

There seems to be a small language problem. There are no VERTICAL members. There ARE Horizontal members.

2x4s tend to measure around 1½" x 3½". Sometimes, they are a bit larger. You must adjust your construction unless you are willing to plane to exact.

From your vertical 26", subtract a 2x4 from each end, (2x3.5") leaving 19" for the total Vertical Measurement of the crossed supports.

From your horizontal 18", subtract 2" from each end, leaving 14" for the total Horizontal Measurement of the crossed supports.

Okay, let's stop there and see if you are following.

Edit: I had the horizontal 2x4 turned the wrong direction. It's taller, now.