Books Books An exterior angle of a triangle is equal to the sum of the two opposite interior angles. Junior High School Mathematics ... - Page 25
by Edson Homer Taylor, Fiske Allen - 1923 ## Plane and Solid Geometry

Claude Irwin Palmer, Daniel Pomeroy Taylor - Geometry - 1918 - 436 pages
...Prolong AC to F. Draw CE-\\ AB. Z4 = Zz. § 133 §132 ' = 180°. §60 = 180°. §111 144. Theorem. An exterior angle of a triangle is equal to the sum of the opposite interior angles, and is therefore greater than either of them. §105 Why? .'. ZBCF>ZA... ## Schultze and Sevenoak's Plane and Solid Geometry

Arthur Schultze, Frank Louis Sevenoak - Geometry - 1918 - 486 pages
...the base of an isceles triangle perpendicular to the arms are equal. PROPOSITION XXIII. THEOREM 117. An exterior angle of a triangle is equal to the sum of the two remote interior angles. B c " Given the ext. Z ACD of A ABC. To prove Z ACD = ZA + Z B. HINT.... ## Solid Geometry

Claude Irwin Palmer - Geometry, Solid - 1918 - 192 pages
...Theorem. The sum of the angles of a triangle is equal to 180°, or two right angles. § 144. Theorem. An exterior angle of a triangle is equal to the sum of the opposite interior angles, and is therefore greater than either of them. § 146. Theorem. In a triangle,... ## Junior High School Mathematics: first and third course, Volume 3

William Ledley Vosburgh - 1919 - 332 pages
...of the isosceles triangle. 7. Find the value of each angle of an equilateral triangle. 8. Prove that an exterior angle of a triangle is equal to the sum of the two opposite interior angles. (SUGGESTION. In Fig. 116, extend AB through B; draw a line through B \\ AC.) Q 9. ABC (Fig. 118) is... ## General Mathematics, Book 1

Raleigh Schorling, William David Reeve - Mathematics - 1919 - 520 pages
...acute angles are 30° and 60° the side opposite the 30-degree angle is one half the hypotenuse. 6. An exterior angle of a triangle is equal to the sum of the two nonadjacent interior angles. 7. The sum of the interior angles of a quadrilateral- is four... ## Plane Geometry

Herbert Edwin Hawkes, William Arthur Luby, Frank Charles Touton - Geometry, Modern - 1920 - 328 pages
...adjacent side produced. See Z 2 of § 69. QUERY. How many exterior angles has a triangle? 69. Corollary 2. An exterior angle of a triangle is equal to the sum of the two opposite interior angles. . HINTS. ./l + Z2 = 2rt. A. Why? = 2rt.A. Why? ABK Hence Zl + Z2 = Z1 + ^A + ZC. Why? Therefore Z2=ZA... ## Elementary Functions and Applications

Arthur Sullivan Gale, Charles William Watkeys - Functions - 1920 - 464 pages
...bisects the base perpendicularly. (b) In any plane triangle the sum of the angles is 180°. (c) The exterior angle of a triangle is equal to the sum of the two opposite interior angles. (d) In a right triangle the square on the hypotenuse is equal to the sum of the squares on the other... ## Maths Matters, Level 4, Module 2, Part 2, Part 3

Competency-based education - 1999 - 116 pages
...a , + a2 = 1 80° angles on a straight line AAAAA .*. al + b+ c= al + a2 AAA /. b+ c = a7 Note: The exterior angle of a triangle is equal to the sum of the two opposite interior angles. 5. Calculate the size of the unknown angles in the following diagrams. /30C Exercise 5.6 Tessellation... ## Calculus: An Intuitive and Physical Approach

Morris Kline - Mathematics - 1998 - 980 pages
...lines are parallel. Now let us consider two lines p and q which are perpendicular (Fig. 3A-9). Since an exterior angle of a triangle is equal to the sum of the two remote interior angles, we have that A = 90°. Then tan A2 = tan(^, + 90°) = -cot A , = l... 