5.1 Midsegment Theorem and Coordinate Proof Objective: Define and use mid-segment of a triangle and mid-segment theorem to solve problems.
Midsegment of a triangle Midsegment – is a segment that connects the midpoints of two sides of the triangle. Every triangle has 3 midsegments. Label and name the midsegments: DE EF FD AB C D E F
Theorem 5.1 Midsegment Theorem The segment connecting the midpoints (midsegment) of two sides of a triangle is parallel to the third side and is half as long as that side. DE = ½ AB DE || AB AB C D E
Given DE is a midsegment Label the diagram and find the length of AB A B C D E 43 Length of AB = 2 x 43 = 85
Place the figure in a coordinate plane in a convenient way. Assign coordinates to each vertex. Right triangle: leg lengths are 5 units and 2 units. Figures in a Coordinate Plane (0, 0) (2, 0) (0, 5)
Geometry Homework 11/10/14 Pages 298-299: Exercises: 3-5 all, 6-18 Even, 24-26 all