 | George Albert Wentworth - 1889 - 276 pages
...each. 39. Corollary. Two right triangles are equal if their legs are equal, each to each. 40. Theorem. In an isosceles triangle the angles opposite the equal sides are equal. 41. Corollary. An equilateral triangle is equiangular. 42. Theorem. If in a triangle two angles are... | |
 | James Wallace MacDonald - Geometry - 1889 - 80 pages
...triangle is equal to the sum of the two opposite interior angles. Proposition XXXIV. A Theorem. 71. In an isosceles triangle the angles opposite the equal sides are equal. Proposition XXXV. A Theorem. 72. If two angles of a triangle are equal, the sides opposite these angles... | |
 | James Wallace MacDonald - Geometry - 1894 - 76 pages
...triangle is equal to the sum of the two opposite interior angles. Proposition XXXIV. A Theorem. 71. In an isosceles triangle the angles opposite the equal sides are equal. COROLLARY. An equilateral triangle is also equiangular. Proposition XXXV. A Theorem. 72. If two angles... | |
 | Education - 1890 - 770 pages
...four hypotheses regarding two straight lines from which they can be proved parallel. 4. Prove that in an isosceles triangle the angles opposite the equal sides are equal. 5. When are polygons mutually equiangular ? Explain the term homologous sides. 6. To what is the sum... | |
 | Edward Albert Bowser - Geometry - 1890 - 420 pages
...triangle is 40° 14' 48", what is the value of the other acute angle ? Proposition 25. Theorem. 111. In an isosceles triangle the angles opposite the equal sides are equal. Hyp. Let ABC be an isosceles A having AC = BC. To prove /_ A = Z B. Proof. Draw the line CD from the... | |
 | Seth Thayer Stewart - Geometry - 1891 - 428 pages
...XIV. 5§1. Theorem Many propositions fire equally true with spherical and plane triangles ; thus, I. In an isosceles triangle, the angles opposite the equal sides are equal. II. If two angles of a triangle are equal, the sides opposite are equal. III. If a triangle is equilateral,... | |
 | Thomas J. Foster - Coal mines and mining - 1891 - 444 pages
...greater side is opposite the greater angle, and the greater angle is opposite the greater side. 7. In an isosceles triangle the angles opposite the equal sides are equal. 8. In any triangle the sum of the three angles is equal to two right angles, or 180°. 9. If two angles... | |
 | Euclid, John Bascombe Lock - Euclid's Elements - 1892 - 188 pages
...[or, The angles at the base of an isosceles triangle are equal to each other. ,] Let ABC represent a triangle in which the side AB is equal to the side AC ; it is required to prove that the angle ACB, opposite to AB, is equal to the angle ABC, opposite to... | |
 | George Bruce Halsted - Geometry - 1896 - 208 pages
...axis BD, ^ BDC will fall within 4 ADB, and therefore C must fall between A and B. 224. Corollary I. In an isosceles triangle, the angles opposite the equal sides are equal. 225. Corollary II. If two angles of a triangle are equal, the triangle is isosceles. 226. If we join... | |
 | Seth Thayer Stewart - Geometry - 1893 - 262 pages
...SPHERICAL TRIANGLES. 5§1. Many propositions are equally true~with spherical and plane triangles ; thus, I. In an isosceles triangle, the angles opposite the equal sides are equal. Draw arc of great О from vertex to middle of base. The two Дs have respectively = sides (hyp. and... | |
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In an isosceles triangle, the angles opposite the equal sides are equal. Let ABC be an isosceles triangle, in which the side AB is equal to the side AC ; then will the angle B be equal to the angle C. 
