# Secondary-school Mathematics, Book 1

D.C. Heath & Company, 1910 - Mathematics

### Popular passages

Page 122 - Th,e square of the sum of two numbers is equal to the square of the first number plus twice the product of the first and second, plus the square of the second.
Page 175 - The line joining the middle points of two sides of a triangle is parallel to the third side and equal to half of the third side.
Page 177 - If two triangles have two sides of one equal respectively to two sides of the other, but the included angle of the first greater than the included angle of the second, then the third side of the first is greater than the third side of the second.
Page 176 - The sum of two sides of a triangle is greater than the third side, and their difference is less than the third side.
Page 177 - The. sum of the angles of any polygon is equal to twice as many right angles as the polygon has sides, less four right angles.
Page 122 - ... the square of the second. _ Again, (a — by = (a — 5) (a — 5) = a2 — 2a6 + 52. (2) That is, The square of the difference of two quantities is equal to the square of the first, minus twice the product of the first by the second, plus the square of the second.
Page 55 - Two triangles are equal if two sides and the included angle of the one are equal respectively to two sides and the included angle of the other (sas = sas). Hyp. In A ABC and A'B'C', AB = A'B', BC = B'C', and Z B = Z B'.
Page 176 - Two triangles are congruent if (a) two sides and the included angle of one are equal, respectively, to two sides and the included angle of the other...
Page 109 - Two triangles on the same sphere or on equal spheres are either equal or symmetrical, if two sides and the included angle of one are respectively equal to two sides and the included angle of the other.
Page 52 - A right-angled triangle (Fig. 24) is any triangle having one right angle. The side opposite the right angle is called the hypotenuse.