 | Industrial arts - 1824 - 726 pages
...divide the parallelogram into two pairs of identical triangles ; viz., CED identical to A £ B, and AEC indentical to EBD, the truths of which will be evident...on each other. Corollary 2. Hence also if one angle of1 a parallelogram is ft right angle, all the other angles will also be right angles, and in that... | |
 | Industrial arts - 1824 - 512 pages
...divide the parallelogram into two pair* of identical triangles ; viz., CED identical to AEB, and AEC indentical to EBD, 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... | |
 | Charles Davies, William Guy Peck - Electronic book - 1855 - 592 pages
...and two. The opposite eidce are equal to each other, taken in pain, as are also the opposite angles. If one angle of a parallelogram is a right angle, all the other angles are also right angles, and the parallelogram is a rectangle. If two adjacent sides of a parallelogram... | |
 | Simon Newcomb - Geometry - 1881 - 418 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... | |
 | Alfred Hix Welsh - Geometry - 1883 - 326 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 - 346 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... | |
 | William Chauvenet, William Elwood Byerly - Geometry - 1887 - 331 pages
...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 - 266 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.... | |
 | Edward Brooks - Geometry, Modern - 1901 - 278 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 - 462 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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If one angle of a parallelogram is a right angle, all the other angles are right angles, and the figure is a rectangle. 
