PPT-4.9: Isosceles & equilateral triangles

Recall that an isosceles triangle has at least two congruent sides The congruent sides are called the legs The vertex angle is the angle formed by the legs The side opposite the vertex angle is called the . A geometric realization of a proof in . H. Wu’s “Teaching Geometry According to the Common Core Standards”. B. A. C. c. a. b. Given a right triangle . . ABC with legs . a. and . b. and hypotenuse . Congruent Triangles. Dr J Frost (jfrost@tiffin.kingston.sch.uk. ). www.drfrostmaths.com. . Last modified: . 31. st. August 2015. Associated Resources: GCSEQuestions-Congruence.doc. GCSE Revision Pack Refs: 169, 170. Classifying Triangles by Angles. ACUTE. OBTUSE. RIGHT. EQUIANGULAR. ACUTE TRIANGLE. All interior angles are acute (or have a measure less than 90°). Interior Angle. Example of Acute Triangle. Phineas’s. Topic 5: Relationships Within Triangles. 5-6: Indirect Proof. Pearson Texas Geometry ©2016 . Holt Geometry Texas ©2007. . TEKS Focus:. (6) Use the process skills with deductive reasoning to prove and apply theorems by using a variety of methods such as coordinate, transformational, and axiomatic and formats such as two-column, paragraph, and flow chart. Marina Kozyr. Icosahedron. You can add appropriate pictures, videos, music.. Regular polyhedron with 20 faces. All faces . are. equilateral triangles.. Regular means all sides and all angles are congruent. Sec: 4.6. Sol: G.5. Properties of Isosceles Triangles. An isosceles triangle is a triangle with two congruent sides.. The congruent sides are called legs and the third side is called the base.. 3. Leg. th. Grade. TRIANGLES. Triangles. A polygon with three sides. Is the simplest of the polygons. Formed by three straight lines. The interior angles add up to 180 degrees. Exterior angles add up to 360 degrees.. Triangles. L.E.Q. How do you use and apply properties of isosceles triangles to solve problems. ?. Parts of an Isosceles Triangle. .. Between the 2 legs.. Surround the base.. If 2 sides of a triangle are congruent, then the angles opposite those sides are congruent.. Objective. :. To understand and apply properties of isosceles and equilateral triangles.. Supplies. :. Math Notebook. Assignment: 4.8 p. 276: 1-10, 12-16, 22-26. 4.8: Isosceles & Equilateral Triangles. Lewis Carroll/Charles Dodgson. Some . fun facts:. .. as a mathematician, Dodgson was, in the words of . . Peter Heath: "An inveterate publisher of trifles [who] was forever putting out pamphlets, papers, broadsheets, and books on mathematical topics [that] earned him no reputation beyond that of a crotchety, if sometimes amusing, controversialist, a compiler of puzzles and curiosities, and a busy yet ineffective reformer on elementary points of computation and instructional method. In the higher reaches of the subject he made no mark at all, and has left none since." . Geometry. 5.1 Angles of Triangles. Essential Question. How are the angle measures of a triangle related?. 5.1 Angles of Triangles. November 21, 2016. 5.1 Angles of Triangles. November 21, 2016. Goals – . Chapter 4. This Slideshow was developed to accompany the textbook. Larson Geometry. By Larson. , R., Boswell, L., . Kanold. , T. D., & Stiff, L. . 2011 . Holt . McDougal. Some examples and diagrams are taken from the textbook.. Magic Triangles. There are 3 magic triangles, two of which are on your formula sheet. They let you do some trigonometric equations without calculators. These are a fundamental part of ”exact solutions” . Geometry. Legs are congruent. Isosceles Triangle. Vertex Angle. Base Angles. Legs. Theorem 4-3 (Isosceles Triangle . Thm. ):. If two sides of a triangle are congruent, then the angles opposite those sides are congruent..