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Warm Up: Draw each regular polygon and find an exterior angle and it’s interior angle. Equilateral Triangle Square Hexagon. Review. If the measure of one exterior angle of a regular polygon is 72º, how many sides does the polygon have?
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Warm Up: Draw each regular polygon and find an exterior angle and it’s interior angle. Equilateral Triangle Square Hexagon
Review • If the measure of one exterior angle of a regular polygon is 72º, how many sides does the polygon have? • What is the measure of one of its interior angles?
Proportions in TrianglesToolkit #8.5 Today’s Goal(s): To use the Side-Splitter Theorem. To us the Triangle-Angle Bisector Theorem.
Side-Splitter TheoremFor three parallel lines… • If three parallel lines intersect two transversals, then the segments intercepted on the transversals are proportional.
Triangle-Angle Bisector Theorem • If a ray bisects an angle of a triangle, then it divides the opposite side into two segments that are proportional to the other two sides of the triangle.
Ex.2 cont…The segments joining the sides of trapezoid RSTU are parallel to its bases.
Ex.3:Using the Triangle-Angle Bisector Thm.Find the value of x. a.) b.)
Perimeters and Areas of Similar FiguresToolkit #8.6 Today’s Goal(s): To find the perimeters and areas of similar figures.
If the similarity ratio of two similar figures is a : b, then… • The ratio of their PERIMETERS is a : b. • The ratio of their AREAS is a2 : b2.
The ratio of their PERIMETERS is a : b. • The ratio of their AREAS is a2 : b2 Sim. Ratio = _____ Per. Ratio = _____ Area Ratio = _____ P = 24 ft P = ?
The ratio of their PERIMETERS is a : b. • The ratio of their AREAS is a2 : b2 Sim. Ratio = _____ Per. Ratio = _____ Area Ratio = _____ A = 4 cm2 A = ?
You Try…(Use the back of your toolkit.)The area of the smaller regular pentagon is about 27.5 cm2.Find the area (A) of the larger regular pentagon. Similarity Ratio = Area Ratio =
STOP and THINK!Are all regular polygons with the same number of sides similar? Yes! Why? All regular polygons are… • Equiangular(angles are congruent) • Equilateral(ratio of sides of any two regular polygons is the same)
a.) Two similar polygons have corresponding sides in the ratio of 5:7. Ex.1:Finding Ratios in Similar FiguresFind the ratio of the perimeters and areas of each pair of similar figures.
EOC REVIEW #7 Tuesday – March 25, 2008 • If ABCD is a rhombus and m<ABC = 60, what is the measure of <1 and <2? • ABCD is a trapezoid. If m<2 = 5x – 20 and m<3 = 3x, find x, y, and m<2 and m<3.
W.B. p. 98 10. 11.