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After remarking that the mathematician positively knows that the sum of the three angles of a triangle is equal to two right angles...
Yale University Entrance Examinations in Mathematics: 1884 to 1898 - Page 125
1898 - 208 pages

## Numerical Problems in Plane Geometry with Metric and Logarithmic Tables

Joe Garner Estill - Geometry - 1896 - 168 pages
...s= — g (Use logarithms.) Princeton, June, 1894. What text-book have you read ? 1. Prove that the sum of the three angles of a triangle is equal to two right angles. Define triangle, right angle, right triangle, scalene triangle. 3. Prove that an angle inscribed...

## Numerical Problems in Plane Geometry: With Metric and Logarithmic Tables

Joe Garner Estill - 1896 - 186 pages
...value. Princeton, June, 1896. State what text-book you have read and how much of it. 1. Prove that the sum of the three angles of a triangle is equal to two right angles ; and that the sum of all the interior angles of a polygon of u sides is equal to (n—2) times...

## Geometry for Grammar Schools

Ephraim Hunt - Geometry - 1896 - 120 pages
...three angles of any triangle ? LESSON XXV. Review Lesson XIV. Draw any scalene triangle. PROBLEM. The sum of the three angles of a triangle is equal to two right angles. Solution. Letter the triangle, and produce the base to D. (1) The exterior angle and its adjacent...

## Helps in the Use of Good English: A Hand-book for All who Desire to ..., Book 1

Albert Newton Raub - English language - 1897 - 272 pages
...substituted. Truism for truth. — A truism is a self-evident truth ; as, " All men are bipeds." " The sum of the three angles of a triangle is equal to two right angles " is a truth, but it needs proof or demonstration, and is not therefore a truism. Try for make....

## Plane and Solid Geometry: Inductive Method

Arthur A. Dodd, B. Thomas Chace - Geometry - 1898 - 490 pages
...logarithms.) Princeton, June, Í896. State what text-book you have read and how much of it. 1. Prove that the sum of the three angles of a triangle is equal to two right angles; and that the sum of all the interior angles of a polygon ofя sides is equal to (n — 2) times...

## Plane and Solid Geometry

James Howard Gore - Geometry - 1898 - 232 pages
...a triangle is greater than the difference of the other two sides. PROPOSITION XII. THEOREM. 79. The sum of the three angles of a triangle is equal to two right angles. Let ABC be any triangle. To prove that Z A + Z B + Z BC A is equal to two right angles. From...

## A History of Elementary Mathematics

Florian Cajori - Mathematics - 1898 - 512 pages
...short, came to make perfect demonstrations. In this way he arrived unaided at the theorem that the sum of the three angles of a triangle is equal to two right angles. His father caught him in the act of studying this theorem, and was so astonished at the sublimity...

## Key to Milne's Plane and Solid Geometry

William James Milne - Geometry - 1899 - 326 pages
.... : the required ¿. = 180° - 76° = 104°. Ex. 59. Show by each of the following figures that the sum of the three angles of a triangle is equal to two right angles, assuming that the construction lines чrе drawn as they appear to be drawn. Proof. (1) §...