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IF a side of any triangle be produced, the exterior angle is equal to the two interior and opposite angles ; and the three interior angles of every triangle are equal to two right angles.
Elements of geometry, containing the first two (third and fourth) books of ... - Page 52
by Euclides - 1871

## Using History to Teach Mathematics: An International Perspective

Victor J. Katz - Mathematics - 2000 - 261 pages
...Heath (1861-1940, English) of Heiberg's text: Proposition 32. In any triangle, if one of the sides be produced, the exterior angle is equal to the two...opposite angles, and the three interior angles of the triangle are equal to two right angles. B D FIGURE 2 The figure is a little different from the...

## The Unfinished Mechanics of Giuseppe Moletti: An Edition and English ...

Giuseppe Moleti, Walter Roy Laird - History - 2000 - 222 pages
...right angle' (Euclid, Elements, 3.31, tr. Heath, 2:61-5). 64 'In any triangle, if one of the sides be produced, the exterior angle is equal to the two...opposite angles, and the three interior angles of the triangle are equal to two right angles' (Euclid, Elements, 1.32, tr. Heath, 1:316-22). 65 'If two...

## Philosophy and Geometry: Theoretical and Historical Issues

L. Magnani - History - 2001 - 249 pages
...universally valid solution of the problem (Kant, 1929, A716-B744, pp. 578-579)." PROP. XXX11. THEOR. 1f a side of any triangle be produced, the exterior angle is equal to the two interiar and oppasite angles ; and the three interior angles af eDery triangle are equal to two right...

## Philosophy and Geometry: Theoretical and Historical Issues

L. Magnani - History - 2001 - 256 pages
...A716-B744, pp. 578-579).13 PROP. XXXII. THEOR. If a side of any triangle be produced, the exterior angle if equal to the two interior and opposite angles ; and the three interior angles of every triangle are equal to tico right angles. Let ABC be a triangle, and let one of its sides BC be produced to D ; the...