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6.4 Parallel Lines and Proportional Parts 6.5 Parts of Similar Triangles. First & Last Name February 26, 2014 ______Block.
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6.4 Parallel Lines and Proportional Parts6.5 Parts of Similar Triangles First & Last Name February 26, 2014 ______Block
Triangle Proportionality Theorem: If a line is parallel to one side of a triangle and intersects the other two sides in two distinct points, then it separates these sides into segments of proportional lengths.
Converse of the Triangle Proportionality Theorem: If a line intersects two sides of a triangle and separates the sides into corresponding segments of proportional lengths, then the line is parallel to the third side.
A midsegment of a triangle is a segment whose endpoints are the midpoints of two sides of the triangle. • Triangle Midsegment Theorem: A midsegment of a triangle is parallel to one side of the triangle, and its length is one-half the length of that side.
3. Triangle ABC has vertices A(-4, 1), B(8, -1), and C (-2, 9). is a midsegment of △ABC. a. Find the coordinates of D and E.
Verify that is parallel to • Verify that
Corollary 6.1: If three or more parallel lines intersect two transversals, then they cut off the transversals proportionally. • Corollary 6.2: If three or more parallel lines cut off congruent segments on one transversal, then they cut off congruent segments on every transversal.
Proportional Perimeters Theorem: If two triangles are similar, then the perimeters are proportional to the measures of corresponding sides.
6. If △LMN ~ △QRS, QR=35, RS=37, SQ=12, and NL=5, find the perimeter of △LMN.
7. Find the perimeter of △WZX, if △WZX~△SRT, ST=6, WX=5, and the perimeter of △SRT=15.
Theorems: If two triangles are similar, then the measures of the corresponding altitudes, angle bisectors, and medians are proportional to the measures of corresponding sides.
9. In the figure, △ABC~△DEF. is a median of △ABC and is a median of △DEF. Find EH if BC=30, BG=15, and EF=15.
10. The drawing below illustrates the position of the camera and the distance from the lens of the camera to the film. Find the height of the sculpture.
Angle Bisector Theorem: An angle bisector in a triangle separates the opposite side into segments that have the same ratio as the other two sides.
Exit Slip • Find the perimeter of △DEF. • Find x. • Use the figure below. • If RL=5, RT=9, and WS=6, find RW. • If TR=8, LR=3, and RW=6, find WS. • Find x and y.