Exploring Proportions in Triangles

Topic:
Triangles
This applet will help you investigate and make conjectures about the relationships among segments formed by parallel lines and angle bisectors in a triangle. Drag any of the vertices of ∆ABC or point D and observe the measurements shown in columns B and C of the spreadsheet shown on the right. Formulate a conjecture based on your observation about the segments of the sides formed by a line cutting two sides of a triangle and parallel to the third side. Drag any of the vertices of ∆FKH and observe the measurements shown in columns B and C again. Based on your observation, formulate a conjecture about the segments formed by the angle bisector and the sides of the angle bisected.