What are the important rays to make a ray diagram?

The "three principal rays" which are used for visualizing the image location and size are: A ray from the top of the object proceeding parallel to the centerline perpendicular to the lens. Beyond the lens, it will pass through the principal focal point.

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The "three principal rays" which are used for visualizing the image location and size are: A ray from the top of the object proceeding parallel to the centerline perpendicular to the lens. Beyond the lens, it will pass through the principal focal point.

Explanation:

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