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Dive into the concept of midsegments of triangles in Saxon Geometry Lesson 55. Explore theorem applications, identifying midpoints, and applying similarity to solve problems. Engage with practice questions and an exit slip for individual assessment.
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Triangle Midsegment Theorem Lesson 55 Saxon Geometry
Essential Questions • What is a midsegment of a triangle? • Which of the side lengths of a triangle is the midsegment’s length half of? • Which of the side lengths of a triangle is the midsegment parallel to? • How is a midsegment triangle related to the original triangle?
New Concepts: Lesson 55 • A midsegment of a triangle is a segment that joins the midpoints of two sides of the triangle. Every triangle has three midsegments. The midsegment is always half the length of the side that does not have a midsegment endpoint on it.
Using the Triangle Midsegment Theorem • In the diagram, DE is a midsegment of ABC. Find the values of x and y.
Your Turn: Using Triangle Midsegment Thm • In the diagram, PQ is a midsegment of LMN. Find the values of x and y.
Using Theorem 55-2 • In the diagram, what are the values of a and b?
Identifying Midpoints of Sides of Triangles • Triangle MNP has vertices M(-2, 4), N(6, 2), and P(2, -1). QR is a midsegment of MNP. Find the coordinates of Q and R.
Identifying Midpoints of Sides of Triangles • Triangle ABC has vertices A(-2, 1), B(4, 3), and C(2,-2). DE is a midsegment of ABC parallel to AC . Find the coordinates of D and E.
Applying Similarity to Midsegment Problems • Triangle STU is the midsegment triangle of PQR. • a. Show that STU ∼ PQR. • b. Find PQ.
Your Turn! Applying Similarity • Triangle NOP is the midsegment triangle of KLM. • a. Show that KLM ∼ NOP. • b. Find the length of LK.
Written Practice • L55 Practice p. 364 a, b, c, d • Please; work with a partner.
Exit Slip • p. 366 #15 & #30 • Individual Assessment