| Iron industry and trade - 1824
...the truths of which will be evident by laying the triangles on each other. Corottary 2. Hence also **if one angle of a parallelogram is a right angle, all the other angles** will also be right angles, and in that case, the diagonals will be equal in length to each other. Note.—... | |
| Perry Fairfax Nursey - Industrial arts - 1824
...the truths of which will be evident by laying the triangles on each other. Corollary 2. Hence also **if one angle of a parallelogram is a right angle, all the other angles** will also be right angles, and in that case, the diagonals will be equal in length to each other. Note.... | |
| Simon Newcomb - Geometry - 1881 - 399 pages
...remaining angles of the one will be equal to the corresponding angles of the other. 125. Corollary 3. **If one angle of a parallelogram is a right angle, all the other angles are** right angles. THEOREM XXVIII. 126. A pair of parallel straight lines intercept equal lengths of parallel... | |
| Alfred Hix Welsh - Geometry - 1883 - 267 pages
...equal. 2. Prove (Th. XII) that the sum of the angles of a quadrilateral equals four right angles. 3. **If one angle of a parallelogram is a right angle, all the** others are right angles. THEOREM XXIV. If the opposite sides of a quadrilateral are equal, the figure... | |
| William Chauvenet - Geometry - 1887 - 322 pages
...* o XXV. Hence the triangles ABC and ADC are equal, by Proposition VII. EXERCISES. 1. Theorem. — **If one angle of a parallelogram is a right angle. all the** angles are right angles, and the figure is a rectangle. 2. Theorem. — If two angles have the sides... | |
| W. E. BYERLY - 1887
...Proposition XXV. Hence the triangles ABC and AD C are equal, by Proposition VII. EXERCISES. 1. Theorem. — **If one angle of a parallelogram is a right angle, all the** angles are right angles, and the figure is a rectangle. 2. Theorem. — If two angles have the sides... | |
| Charles Austin Hobbs - Geometry, Plane - 1899 - 240 pages
...is perpendicular to the bisector of the exterior angle at the vertex C. Proposition 61. Theorem. 73. **If one angle of a parallelogram is a right angle, all the other angles are** right angles, and the figure is a rectangle. Proposition 62. Theorem. Proposition 63. Theorem. 75.... | |
| Edward Brooks - Geometry, Plane - 1901 - 266 pages
...sides of the figure are parallel ; therefore the figure is a parallelogram. Therefore, etc. COR. — **If one angle of a parallelogram is a right angle, all the** angles are right angles and the figure is a rectangle. Let the pupil prove it. PROPOSITION XXXI. —... | |
| Thomas Franklin Holgate - Geometry - 1901 - 440 pages
...5. If both pairs of opposite angles of a quadrilateral are equal, the figure is a parallelogram. 6. **If one angle of a parallelogram is a right angle, all the** angles are right angles. 7. If two sides of a quadrilateral are parallel, and the other two equal but... | |
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