PROBLEM IV--Develop an ellipse with a vertical

5. From each point on the inner circle, and parallel

diameter of 6 l/4 inches and a horizontal diameter of 4

to diameter l-l, draw a line toward the outer circle.

7/8 inches. (See fig. 16-8.)

6. From all points on the outer circle, draw lines

SOLUTION:

parallel to diameter 6-6 so that they intersect with the

lines drawn in step 5.

1. Scribe a circle with a 6 l/4-inch diameter.

7. The points of intersection of the vertical and

2. Use the same center and scribe a circle with a 4

horizontal lines in each quadrant are points on the

7/8-inch diameter.

ellipse.

3. Develop the inner circle so that each quadrant

8. Sketch in the outline of the ellipse by freehand

or quarter-circle is equally divided into five parts. (See

drawing, or use a french curve. A true and perfect ellipse

problem I and fig. 16-5 .)

must be developed geometrically. The greater the

4. Locate the equal-space division points on the

number of points established, the more nearly perfect

outer circle circumference by radiating lines from the

the ellipse will be.

center point. These lines are to pass through the division

points on the inner circle's circumference. Number

Sometimes the ellipse does not have to be perfect.

these points as indicated in figure 16-8.

In such cases the ellipse is laid out directly on the deck

16-9