After remarking that the mathematician positively knows that the sum of the three angles of a triangle is equal to two right angles... Introduction and books 1,2 - Page 218by Euclid, Sir Thomas Little Heath, Johan Ludvig Heiberg - 1908Full view - About this book
| William Jay Youmans - Science - 1897
...invention, and judgment" Instead of a series of written proofs to memorize, such as, for instance, the **sum of the three angles of a triangle is equal to two right** angles, the student takes the triangle, and, with suggestions from the teacher where necessary, works... | |
| George Albert Wentworth - Geometry - 1896 - 50 pages
...triangle is greater than the third side, and their difference is less than the third side. 138. The **sum of the three angles of a triangle is equal to two right** angles. 139. Cor. 1. If the sum of two angles of a triangle is subtracted from two right angles, the... | |
| Joe Garner Estill - 1896 - 161 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... | |
| Joe Garner Estill - Geometry - 1896 - 144 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... | |
| Ephraim Hunt - Geometry - 1896
...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... | |
| Albert Newton Raub - English language - 1897 - 260 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.... | |
| Florian Cajori - Mathematics - 1898 - 422 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... | |
| Yale University - Mathematics - 1898 - 208 pages
...circular sheet of tin 16 inches in diameter and weighing 8.2 ounces per square foot. JUNE 1896. (a) 1. The **sum of the three angles of a triangle is equal to two right** angles. 2. Construct a circle having its center in a given line and passing through two given points.... | |
| Arthur A. Dodd, B. Thomas Chace - Geometry - 1898 - 406 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... | |
| James Howard Gore - Geometry - 1898 - 210 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... | |
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