## Procedure

- Problem 3-19 & 3-20 are in Inches, problem 3-21 is Metric.
- Do as many drawings below as you can in the time available.
- Follow the same procedures as the previous tutorials.
- Dimension these drawing.
- For a closeup open problem3_19_to_3_21.pdf and zoom in as needed.
- Center the drawings, scale, print, staple together and hand in to be marked.
**See Hint For Problem 3-19 at Bottom Of This Page!**

## Hint for 3-19 – How to find the center of arc “R”

- First draw as much as you can.
- From the center of the 0.25 radius arc (center mark on the left) draw a 1.88 radius circle.
- 1.88 is derived from adding the 0.25 and 1.63 arcs
- 0.25 + 1.63 = 1.88

- From the center of the 4.18 diameter circle (center mark on the right) draw a 0.96 radius circle.
- 0.96 is derived from finding the radius of the 4.18 diameter circle and dividing by 2 to get the radius then subtracting for the 1.13 radius arc
- 4.18 ÷ 2 – 1.13 = 0.96

- The “R” radius arc is drawn from the center to the TANGENT of the R3.0 circle.
- The R1.13 radius arc is drawn from the center to the TANGENT of the 4.18 diameter circle.