 | Alan Sanders - Geometry, Modern - 1901 - 260 pages
...of the other pair of vertical angles. Find the values of the four angles. PROPOSITION X. THEOREM 81. In an isosceles triangle, the angles opposite the equal sides are equal. Let ABC be an isosceles A, having AB = BC. To Prove Z A = Z C. Proof. Draw BD bisecting AC. (§ 55.) B and D are each equally... | |
 | Henry Parker Manning - Geometry, Non-Euclidean - 1901 - 120 pages
...the included angle, of one Kqual, respectively, to the corresponding parts of the other. 4. Theorem. In an isosceles triangle the angles opposite the equal sides are equal. Bisect the angle at the vertex and use (3). 5. Theorem. The perpendiculars erected at the middle points... | |
 | Thomas Franklin Holgate - Geometry - 1901 - 462 pages
...third side has also the greater included angle. § 80. 9. THEOREMS ON THE PROPERTIES OF TRIANGLES. (1) In an isosceles triangle, the angles opposite the equal sides are equal. § 48. (2) The straight line which bisects the vertical angle of an isosceles triangle also bisects... | |
 | Henry Parker Manning - Geometry, Non-Euclidean - 1901 - 122 pages
...the included angle, of one equal, respectively, to the corresponding parts of the other. 4. Theorem. In an isosceles triangle the angles opposite the equal sides are equal. Bisect the angle at the vertex and use (3). 5. Theorem. The perpendiculars erected at the middle points... | |
 | Edward Brooks - Geometry, Modern - 1901 - 278 pages
...triangles coincide in all their parts and are equal. Therefore, etc. PROPOSITION XXI. — THEOREM. In an isosceles triangle the angles opposite the equal sides are equal. Given. — Let ABC be an isosceles triangle having the side AC equal to the side BC. To Prove. —... | |
 | Henry Parker Manning - Geometry, Non-Euclidean - 1901 - 116 pages
...the included anyle, of one equal, respectively, to the corresponding parts of the other. 4. Theorem. In an isosceles triangle the angles opposite the equal sides are equal. Bisect the angle at the vertex and use (3). 5. Theorem. The perpendiculars erected at the middle points... | |
 | George Albert Wentworth - Geometry, Solid - 1902 - 248 pages
...angle of the other. 144. Two right triangles are equal if their legs are equal, each to each. 145. In an isosceles triangle the angles opposite the equal sides are equal. 147. If two angles of a triangle are equal, the sides opposite the equal angles are equal, and the... | |
 | Alan Sanders - Geometry - 1903 - 392 pages
...of the other pair of vertical angles. Find the values of the four angles. PROPOSITION X. THEOREM 81. In an isosceles triangle, the angles opposite the equal sides are equal. Let ABC be an isosceles A, having AB = BC. To Prove ZA = /L C. Proof. Draw BD bisecting AC. (§ 55.) B and D are each equally... | |
 | American School (Chicago, Ill.) - Engineering - 1903 - 390 pages
...coincide throughout and are equal. THEOREH XXI. 82. In an isosceles triangle the angles opposite ihe equal sides are equal. Let ABC be an isosceles triangle in which AC and BC are the equal sides. To prove that angle A — angle B : Draw CD perpendicular to A B. There... | |
 | Euclid - Euclid's Elements - 1904 - 488 pages
...equal sides be produced, the angles on the other side of the base shall also be equal to one another. A Let ABC be an isosceles triangle, in which the side AB is equal to the side AC, and let the straight lines AB, AC be produced to D and E. Then (i) the angle ABC shall be equal to... | |
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In an isosceles triangle, the angles opposite the equal sides are equal. 
