Area Trisection 5
Quadrilateral DEFH is a parallelogram with side DE one-third of side BC and side EF half the length of the median drawn from vertex A and parallel to it. Point I is the midpoint of segment HF.
Intersecting Tangent Secant Angle Theorem and Proof
Tangente de la secante
Unit Circle to Trig Graphs
Visual proofs of the sums of infinite geometric series, r<1의 복사본