Book, Paragraph

 1      I, 24| geometrical proofs, e.g. that the angles at the base of an isosceles
 2      I, 24|           claiming generally that angles of semicircles are equal;
 3      I, 24|     should assume that when equal angles are taken from the whole
 4      I, 24|          are taken from the whole angles, which are themselves equal,
 5      I, 35|         Let A stand for two right angles, B for triangle, C for isosceles
 6      I, 35|         nature contains two right angles, consequently there will
 7     II, 17|      contains more than two right angles.~
 8     II, 21|         let A stand for two right angles, B for triangle, C for a
 9     II, 21|       triangle contains two right angles; consequently he will know
10     II, 21|       that every triangle has its angles equal to two right angles"
11     II, 21|         angles equal to two right angles" is ambiguous, meaning to
12     II, 21|         that C contains two right angles with a knowledge of the
13     II, 21|           directly; e.g. that the angles are equal to two right angles,
14     II, 21|     angles are equal to two right angles, if we know that the figure