Question

desargeus theorom proof​

Answer 1

Required Answer ✅

: Let O be the common point of A1A2, B1B2, C1C2 and suppose , in the first case, that C1 is not in the plane OA1B1. Since A1A2 and B1B2 meet at O, they are in the same plane which meets the line l in the point ab. In the same way ca and bc must be on l as required.

Answer 2

Answer:

Three-dimensional proof

Desargues's theorem can be stated as follows: If lines Aa, Bb and Cc are concurrent (meet at a point), then. the points AB ∩ ab, AC ∩ ac and BC ∩ bc are collinear. The points A, B, a and b are coplanar (lie in the same plane) because of the assumed concurrency of Aa and Bb.