...make the point C move in two directions at once, (namely, at right angles to AC, and at right angles to BC,) which is impossible, and therefore the angles...parallelogram. — Proof. If in the quadrangle ABCD (Fig. B.), the sides AB and CD are equal, and also the sides AD and BC are equal, then, by drawing...

...point С move in two directions at once, (namely, at right angles to AC, and at right angles to В С,) which is impossible, and therefore the angles cannot...is a parallelogram. — Proof. If in the quadrangle А В С D (Fig. В.), the sides А В and С D are equal, and also the sides AD and В С are equal,...

...point С move in two directions at once, (namely, at right angles to AC, and at right angles to В С,) which is impossible, and therefore the angles cannot...is a parallelogram. — Proof. If in the quadrangle А В С D (Fig. В.), the sides AB and С D are equal, and also the sides AD and В С an; equal,...

...opposite to these angles are also equal . . (Euc. I. 6) 119 Congruence. C.8. — If the three sides of one triangle are respectively equal to the three sides of another triangle, the two triangles shall be congruent (Euc. I. 8) 120 C.4. — If the hypotenuse and one side of one right-angled...

...all respects. If two angles of a triangle are equal, the sides opposite the equal angles are equal. If the three sides of a triangle are respectively equal to the "ihre* sides of another triangle, the triangles are equal in all respects. The straight line joining...