# Stengel's Theorem

Stengel's Theorem

Let ABC be a triangle. Let E, D, and G be points on AB, BC, and AC, respectively. Let EC intersect AD at F. Choose points I, J, and H so that EI || BG || FJ || DH.

Then +=+.

1

EI

1

DH

1

FJ

1

BG

Drag the triangle's vertices or the sliders to change the figure.