When a plane intercept is at infinity, what should you do according to the method?

• A. Draw a line across possible points and span out line
• B. Take reciprocal of the infinity
• C. Encase in parentheses
• D. Move axis to the nearest plane

Answer: (A)

When a plane’s intercept with an axis is at infinity, the plane runs parallel to that axis. In practice, you can’t mark a finite intercept on that axis, so you build the plane using the finite intercepts on the other axes. The way to do this is to plot a line that passes through the intercepts you do have (the finite ones) and then extend, or “span out,” that line in the direction of the axis that goes to infinity. By sweeping along that parallel direction, you obtain the whole plane. So the method is to draw a line across the possible intercept points defined by the finite intercepts and then span out along the infinite direction to form the plane.