# How to draw a great circle of a sphere？

I am the distance on the sphere? I wonder how to draw a section of a sphere with Sktechpad or other tools?

Since the sphere is shown on the plane, how to draw the great circle?

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When you project the sphere down into the plane, you are applying a linear transformation. Merely apply the same transformation to the great circle. – Isaac Solomon Mar 15 '12 at 2:12

Let $C$ be the circle representing the sphere in your drawing. The images of great circles are ellipses whose center of symmetry coincides with the midpoint of $C$, and which touch $C$ in two points.