Hatfield, Robert Griffith, 1815-1879. [from old catalog] · New York & London, Wiley and Putnam · leaf 73
lels, a d and b e, they are therefore equal, {Art. 145, 146 ;) andsince the triangle, C, is common to both, the remaining triangles, Aand B, are therefore equal; then B being equal to A, the triangle,a e c, is equal to the quadrangle, abed. … Fig. 105. 148.—Proposition. If two straight lines cut each other, asa b and c d, {Fig. 105,) the vertical, or opposite angles, A andC, are equal. Thus, a e, standing upon c d, forms the angles,B and C, which together amount, {Art. 137,) to two right angles;in the same manner, the angles, A and B,…
Carpentry · Architecture
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