This post comes as a response to help a reader complete the exercise on Learn AutoCAD basics – Day 18
Here is what the final image of this project is like.
Draw these circles
The red line is a straight line. On the upper side, it intersects with the green circle R144 allowing us to place the two circles R15 (Use the information about the angle to place them, the black line is horizontal). On the lower side, the same red line intersects with the blue circles R225 (resulting from 150+75) and R150, each of the intersecting point should allow you to find the centers of the two blue circles R20.
The red circles, R56 and R18 have the same center which you can find using information from the exercise.
Delete other circle and create the two new one on the picture below. (R129 and R159)
Delete R144. Trim the 2 biggest circles and the two green circles such as to have the following.
OFFSET the piece we just created with an offset distance of 15. Join the two blue circles with straight lines and trim them such as to have the following.
Use the tan tan Radius technique to get these circles created.
Create a line from the end of the blue arc and tangent to R60 as shown below
Trim all unnecessary parts and There you have it!