Definition: Two triangles $\triangle_1 = \triangle(A_1, B_1, C_1)$ and $\triangle_2 = \triangle(A_2, B_2, C_2)$ are in perspective w.r.t. a point $S$ if \[ S = (A_1 A_2) \cap (B_1 B_2) \cap (C_1 C_2) \] The triangles are in perspective w.r.t. … Continue reading Lecture 4