Steps:

1. Draw a circle with a radius of 35.
2. Sketch the contour line at the bottom left corner.
3. Offset it upwards by 38 units and draw auxiliary lines to locate the middle arc.
4. Draw a circle with a central radius of 25 using the CircleTTR command. Make it tangent to the circle and auxiliary line on the left.
5. Prepare to draw the rightmost arc. Since the distance between the centers of the two circles is 60 units, use the middle circle as the center and draw a circle with a radius of 60 as the auxiliary line.
6. Draw a vertical line at the right end of the straight line, intersecting the circle with a radius of 60, to determine the position of the circle’s center.
7. Draw a circle with a radius of 35. Once the rightmost circle is drawn, remove the auxiliary line.
8. Apply a fillet of 15. Use the TTR command to draw a tangent circle with a radius of 75.
9. Trim the necessary elements and add annotations as required.