| John Wesley Young, Albert John Schwartz - Geometry, Plane - 1915 - 223 pages
...two adjacent sides of a parallelogram are equal, all the sides are equal. § 232 237. COROLLARY 7. **If one angle of a parallelogram is a right angle, all the** angles are right angles. § 235 Dt \G BA ~ — B FIG. 104. FIG. 105. 238. A rectangle. If one angle... | |
| William Ledley Vosburgh, William Frederick Gentleman - Mathematics - 1919
...of a parallelogram is equal to 180° (Fig. 125). Fio. 125. (SUGGESTION. Z1=ZCr. Why?) 4. Prove that **if one angle of a parallelogram is a right angle all the** angles are right angles. § 123. THEOREM V. The diagonals of a parallelogram bisect each other. DC... | |
| Charles Austin Hobbs - Geometry, Solid - 1921 - 192 pages
...parallel lines are equal. Prop. 54. The opposite angles of a parallelogram are equal. Prop. 54, Cor. // **one angle of a parallelogram is a right angle, all the other angles are** right angles, and the figure is a rectangle. Prop. 55. The diagonals of a parallelogram bisect each... | |
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