5 4 The Triangle Midsegment Theorem Drill Thursday

5 -4 The Triangle Midsegment Theorem Drill: Thursday, 12/10 Use the points A(2, 2), B(12, 2) and C(4, 8) for Exercises 1– 5. 1. Find the midpoints of AC and CB. 2. Find the distance between the two midpoints from problem #1. 3. Find AB. 4. Find the slope of AB. Objective: Prove and use properties of triangle midsegments. Holt Mc. Dougal Geometry

5 -4 The Triangle Midsegment Theorem 5. 4 Midsegment of a Triangle Objectives: • Identify the midsegments of a triangle. • Use properties of midsegments of a triangle. Holt Mc. Dougal Geometry

5 -4 The Triangle Midsegment Theorem A midsegment of a triangle is a segment that joins the midpoints of two sides of the triangle. Every triangle has three midsegments, which form the midsegment triangle. Holt Mc. Dougal Geometry

5 -4 The Triangle Midsegment Theorem The relationship shown in Example 1 is true for the three midsegments of every triangle. Holt Mc. Dougal Geometry

5 -4 The Triangle Midsegment Theorem x = 23 x 46 Holt Mc. Dougal Geometry

5 -4 The Triangle Midsegment Theorem x =10 3 x 4 x + 20 Holt Mc. Dougal Geometry

A Explain how you would be able to use the triangle midsegment theorem in order to find the distance across the lake? B

5 -4 The Triangle Midsegment Theorem x=8 2 x + 10 7 x – 4 Holt Mc. Dougal Geometry

5 -4 The Triangle Midsegment Theorem Lesson Quiz: Part I Use the diagram for Items 1– 3. Find each measure. 1. ED 10 2. AB 14 3. m BFE 44° Holt Mc. Dougal Geometry

5 -4 The Triangle Midsegment Theorem Lesson Quiz: Part II 4. Find the value of n. 16 5. ∆XYZ is the midsegment triangle of ∆WUV. What is the perimeter of ∆XYZ? 11. 5 Holt Mc. Dougal Geometry