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G4.3: The Midsegment Theorems. Goal 1 Using Midsegments of Triangles and Trapezoids. Goal 2 Using Properties of Midsegments. Concept: Triangle Midsegment Theorem.
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G4.3: The Midsegment Theorems Goal 1 Using Midsegments of Triangles and Trapezoids. Goal 2 Using Properties of Midsegments.
Concept: Triangle Midsegment Theorem • If a segment joins the midpoints of two sides of a triangle, then the segment is parallel to the third side and is half as long.
Concept: Identifying Parallel Segments • What are the three pairs of parallel segments in triangle DEF? • RS || ____ • ST || ____ • TR || ____
Concept: Similar Triangles The midsegment of a triangle creates 2 similar triangles ∆XYZ ~ ∆UVZ LYXZ = LVUZ so mLVUZ = 65º Find the mLVUZ. X 65O U Z Y V
Concept: Using Midsegments of a Triangle a) In ∆XYZ, which segment is parallel to b) Find YZ and XY
Concept: Using Midsegments of a Triangle cont. In the diagram, ST and TU are midsegments of triangle PQR. Find PR and TU. 5 ft 16 ft TU = ________ PR = ________
Concept: Using Midsegments of a Triangle cont. In the diagram, XZ and ZY are midsegments of triangle LMN. Find MN and ZY. 14 cm 53 cm ZY = ________ MN = ________
52 Example 6 In the diagram, ED and DF are midsegments of triangle ABC. Find the value of x and DF. 3x- 4 x = ________ 10 DF = ________ 26
You Try! Given: DE = x + 2; BC = Find the value of x and DE. x + 2
Concept: Trapezoid definition A Trapezoid is a quadrilateral with only one pair of parallel sides.
Concept: Isosceles Trapezoid Isosceles Trapezoids have congruent legs. In a Isosceles Trapezoid each pair of base angles are congruent.
Concept: Definition of a Trapezoid Midsegment Midsegment connect the midpoints of the legs. EF is the midsegment of trapezoid ABCD
Concept: Trapezoid Midsegment Formula The Midsegmentis equaltohalf the sum of the parallal sides.
Concept: Trapezoid Midsegment Formula Example: Find NO The Midsegment equal half the parallel sides sum.
Concept: Trapezoid Midsegment Formula Example: Find the value of x. The Midsegment equal half the parallel sides sum. x = 3