Books Books An exterior angle of a triangle is equal to the sum of the two opposite interior angles. Junior High School Mathematics ... - Page 29
by Edson Homer Taylor, Fiske Allen - 1923 ## Plane Geometry: With Problems and Applications

Herbert Ellsworth Slaught, Nels Johann Lennes - Geometry, Plane - 1910 - 300 pages
...of these two propositions has been studied extensively during the last two centuries. 103. THEOREM. An exterior angle of a triangle is equal to the sum of the two opposite interior angles. The proof is left to the student. Compare this theorem with that of § 83. 104. Definition. A theorem... ## Second-year Mathematics for Secondary Schools, Volume 2

George William Myers - Mathematics - 1910 - 304 pages
...of another, the third angles are equal, and the triangles are mutually equiangular. 12. Prove, that an exterior angle of a triangle is equal to the sum of the two opposite interior angles of the triangle. 13. One base angle of an isosceles triangle is ^ of the vertex-angle. Find the angles... ## Secondary-school Mathematics, Book 1

Robert Louis Short, William Harris Elson - Mathematics - 1910 - 200 pages
...equal, respectively, to the leg and acute angle of the other. 3. Prove that the exterior angle (§ 122) of a triangle is equal to the sum of the two opposite interior angles. (You will need this theorem very often.) 4. Prove that the exterior angle of a triangle is greater... ## Elements of Plane Geometry

William Herschel Bruce, Claude Carr Cody (Jr.) - Geometry, Modern - 1910 - 284 pages
...exterior angle of a triangle is greater than either of the non-adjacent interior angles. 158. COR. 3. An exterior angle of a triangle is equal to the sum of the two non-adjacent interior angles. 159. COR. 4. If two triangles have two angles of the one equal... ## Special Reports on Educational Subjects, Volume 24

Great Britain. Board of Education - Education - 1911 - 678 pages
...lesson in Quarta (to boys aged eleven) on the same proposition, or rather on the theorem that " every exterior angle of a triangle is equal to the sum of the two opposite interior angles," from which the theorem relating to the sum of the three angles of a triangle is deduced. The lesson,... ## Plane Geometry

Clara Avis Hart, Daniel D. Feldman - Geometry, Modern - 1911 - 332 pages
...angle and the two remote interior angles of the triangle ? B' B ff PROPOSITION XXVIII. THEOREM 215. -An exterior angle of a triangle is equal to the sum of the two remote interior angles. B CD Given £\ABC with Z.DCB an exterior Z. To prove Z DCB = ZA + Z... ## Plane Geometry

William Betz, Harrison Emmett Webb - Geometry, Modern - 1912 - 368 pages
...What is the value of the third angle ? 12. Verify by measurement the fact (to be proved later) that an exterior angle of a triangle is equal to the sum of the two remote interior angles. CLASSIFICATION OF TRIANGLES BASED ON ANGLES 47. A triangle, one of... ## Plane Geometry

William Betz, Harrison Emmett Webb - Geometry, Plane - 1912 - 360 pages
...What is the value of the third angle ? 12. Verify by measurement the fact (to be proved later) that an exterior angle of a triangle is equal to the sum of the two remote interior angles. CLASSIFICATION OF TRIANGLES BASED ON ANGLES 47. A triangle, one of... ## Solid Geometry

Clara Avis Hart, Daniel D. Feldman - Geometry, Solid - 1912 - 226 pages
...hypotenuse and a side of one are equal respectively to the hypotenuse and a side of the other. 213. An exterior angle of a triangle is equal to the sum of the two remote interior angles. 216. The sum of all the angles of any polygon is twice as many right... 