Mech Engineering Four-Bar Linkage Angle Question

[chronie]

Homework Statement

I have a design problem where I have to design a crank rocker and find all the angles. I have already chosen my sides. The crank will move in increments of 30* up until 360.

Homework Equations

**Please see the attachments

The Attempt at a Solution

I have plugged in my values, however when I plot all my angles they do not all equal 360 degrees. If I am correct don't all four of my angles have to be 360 degrees?

In fact the sum of my angles start at 180, increase in increments of 30degrees until 540degrees.

All my sides have obeyed the l1+l2<l3+l4. Can someone explain to me if this is correct or what I am doing wrong.Much Thanks,-c

 

[chronie]

Sorry I forgot to add a picture of the crank