Thus when it is said that the sum of the three angles of any triangle is equal to two right angles, this is a theorem, the truth of which is demonstrated by Geometry. Elements of Mechanical Drawing - Page 22by Gardner Chace Anthony - 1894 - 98 pagesFull view - About this book
| Samuel Hamilton - Arithmetic - 1907 - 422 pages
...equal to 180°. This can also be shown by measuring the angles with a protractor. The sum of all the angles of any triangle is equal to two right angles,- or 180°. The following numbers in each case represent the size of two angles of a triangle. Find the size of... | |
| Joseph Victor Collins - Algebra - 1908 - 442 pages
...APPLICATIONS IN GEOMETRY 154. Some Theorems of Geometry stated algebraically with Exercises. 1. THEOKEM. The sum, of the three angles of any triangle is equal to two right angles, or ISO0. Construct on sheets of paper several triangles like ABC in the margin. Cut the angles off at... | |
| Walter Percy Workman - Geometry - 1908 - 228 pages
...4.) FIG. 487. EXERCISES CX.XVII. EXAMPLES ON INVERSION. 1. Invert the following theorems : — (a) The sum of the three angles of any triangle is equal to two right angles. (b) AB and CD are two parallel lines. A line which is drawn at right angles to AB, is also at right... | |
| Samuel Hamilton - Arithmetic - 1908 - 512 pages
...equal to 180°. This can also be shown by measuring the angles with a protractor. The sum of all the angles of any triangle is equal to two right angles, or 180°. The following numbers in each case represent the size of two angles of a triangle. Find the size of... | |
| Joseph Victor Collins - Algebra - 1910 - 332 pages
...APPLICATIONS IN GEOMETRY 154. Some Theorems of Geometry stated algebraically with Exercises. 1. THEOREM. The sum of the three angles of any triangle is equal to two right angles, or 180°. Construct on sheets of paper several triangles like ABO in the margin. Cut the angles off at the dotted... | |
| Joseph Victor Collins - Algebra - 1910 - 332 pages
...APPLICATIONS Ш GEOMETRY 154. Some Theorems of Geometry stated algebraically with Exercises. 1. THEOKEM. The sum of the three angles of any triangle is equal to two right angles, or ISO0. Construct on sheets of paper several triangles like ABC in the margin. Cut the angles off at... | |
| George William Myers - Mathematics - 1910 - 304 pages
...two angles are parallel, right to right and left to left (Fig. .40), the angles are equal. Prove. 3. The sum of the three angles of any triangle is equal to a straight angle, or to two right angles. Prove. (See Fig. 42. See also FYM, pp. 54, 55.) 62. A triangle... | |
| Geometry, Plane - 1911 - 192 pages
...BF = -=-. nn + l JUNE, 1906 (One hour and a half.) The University provides a Syllabus. 1. Prove that the sum of the three angles of any triangle is equal to two right angles. On a line AE choose a point B, and construct an isosceles triangle ABC with AB as base, the base angles... | |
| Walter Burton Ford, Earle Raymond Hedrick - Geometry, Modern - 1913 - 272 pages
...(The quadrilateral formed is called a parallelogram.) PART III. ANGLES AND TRIANGLES 62. Theorem XI. The sum of the three angles of any triangle is equal to two right angles, or 180". Given any triangle ABC. To prove that Z 4 + ZB + Z (7= 2 rt. A. Proof. Prolong AB to D and through... | |
| Walter Burton Ford, Charles Ammerman - Geometry, Plane - 1913 - 378 pages
...(The quadrilateral formed is called a parallelogram.) PART III. ANGLES AND TRIANGLES 62. Theorem XI. The sum of the three angles of any triangle is equal to two right angles, or 18(f. Given any triangle ABC. To prove that Z A + Z B + Z C= 2 rt. A. Proof. Prolong AB to D and through... | |
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