 An exterior angle of a triangle is equal to the sum of the two opposite interior angles, and therefore greater than either of them.  Plane Geometry - Page 33by George Albert Wentworth - 1899 - 256 pagesFull view - About this book
 | Herbert Ellsworth Slaught, Nels Johann Lennes - Geometry, Plane - 1918 - 360 pages
...to an acute angle of another right triangle, the remaining acute angles are equal. 160. COROLLARY 4. An exterior angle of a triangle is equal to the sum of the two opposite interior angles. Suggestion. Zl + Z2+Z3 = 2rt. A, Euclid (about 330-275 BC-), a famous teacher of geometry who lived... | |
 | Herbert Ellsworth Slaught - 1918 - 344 pages
...to an acute angle of another right triangle, the remaining acute angles are equal. 160. COROLLARY 4. An exterior angle of a triangle is equal to the sum of the two opposite interior angles. Suggestion. Zl + Z2+z3 = 2rt. A, Euclid (about 330-275 BC). a famous teacher of geometry who lived... | |
 | 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,... | |
 | 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.... | |
 | Claude Irwin Palmer, Daniel Pomeroy Taylor - Geometry - 1918 - 460 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... | |
 | 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... | |
 | 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... | |
 | 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... | |
 | 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... | |
 | Robert E. Moyer - Mathematics - 1998 - 246 pages
...triangle, the triangles are similar. A The sum of the measures of the angles of a triangle is 1 80°. A An exterior angle of a triangle is equal to the sum of the measures of the two nonadjacent interior angles of the triangle. A The acute angles of a right... | |
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