Elements of geometry : containing the first six books of Euclid, with a supplement on the quadrature of the circle, and the geometry of solids : to which are added, Elements of plane and spherical geometry (1826)
Playfair, John, 1748-1819, Euclid · Philadelphia : Marot & Walter · leaf 17
XXI A scalene triangle, is that which has three unequal sides. XXII.A right angled triangle* is that which has a right angle- 46 ELEMENTS XXIII. An obtuse angled triangle, \s that which has an obtuse angle. … XXIV. An acute angled triangle, is that which has three acute angles. XXV.Of four sided figures, a square is that which has all its sides equal3and all its angles right angles. XXVI. An oblong, is that which has all its angles right angles, but has not all its sides equal. XXVII.A rhombus, is that…
Euclid's Elements · Geometry · Trigonometry
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