 | George Albert Wentworth - Geometry - 1899 - 498 pages
...transversal AC; that is, the line DE bisects AC. 189. COB. 2. The line which joins the middle points of two sides of a triangle is parallel to the third side, and is equal to half the third side. A line drawn through D, the middle point of AB, II to BC, passes through... | |
 | Charles Austin Hobbs - Geometry, Plane - 1899 - 266 pages
...diagonals and the included angle are given. Proposition 64. Theorem. 76. The line joining the middle points of two sides of a triangle is parallel to the third side, and is equal to one half the third side. B 57 Conclusion. DE is II to BC, and DE = \ BC. Proof. Draw CF... | |
 | George Albert Wentworth - Geometry, Solid - 1899 - 248 pages
...triangle and bisects one side, it bisects the other side also. 189. The line which joins the middle points of two sides of a triangle is parallel to the third side, and is equal to half the third side. 190. The median of a trapezoid is parallel to the bases, and is equal... | |
 | William James Milne - Geometry, Modern - 1899 - 258 pages
...the same two points, which by Ax. 12 is impossible. Consequently, the line joining the middle points of two sides of a triangle is parallel to the third side. Proposition XLIII 160. Draw a trapezoid and a line connecting the middle points of the non-parallel... | |
 | Seymour Eaton - 1899 - 362 pages
...altitude, they shall be equal to one another. 2. Prove that the straight line joining the middle points of two sides of a triangle is parallel to the third side. Lesson No. 19 PROPOSITION 42. PROBLEM To describe a parallelogram that shatt be equal to a given triangle,... | |
 | William James Milne - Geometry - 1899 - 398 pages
...the same two points, which by Ax. 12 is impossible. Consequently, the line joining the middle points of two sides of a triangle is parallel to the third side. Proposition XLIII 160. Draw a trapezoid and a line connecting the middle points of the non-parallel... | |
 | Charles Hamilton Ashton - Geometry, Analytic - 1902 - 306 pages
...find the ratio of their distances from each other. 7410. Show that the line joining the middle points of two sides of a triangle is parallel to the third side and equal to one half of it 11. Show that the diagonals of a square or rhombus are perpendicular to each other.... | |
 | Charles Hamilton Ashton - Geometry, Analytic - 1900 - 294 pages
...ratio of their distances from each other. . 10. Show that the line joining the middle points of the sides of a triangle is parallel to the third side and equal to one half of it. 11. Show that the diagonals of a square or rhombus are perpendicular to each other.... | |
 | Euclid, Henry Sinclair Hall, Frederick Haller Stevens - Euclid's Elements - 1900 - 330 pages
...the triangles are equal in area. ON PROP. 39. 10. The straiijht line which joins the middle points of two sides of a triangle is parallel to the third side. 11. If two straight lines AB, CD intersect in O, so that the triangle AOC M equal to the triangle DOB,... | |
 | Arthur Schultze - 1901 - 392 pages
...parallel to the base, bisects the other non-parallel side. PROPOSITION XXXIX. THEOREM 147. A line which joins the midpoints of two sides of a triangle is parallel to the third side and equal to half of it. BC Hyp. In A ABC: AD = DB, AE = EC. To prove 1°. DE II BC. 2°. DE = \BC. Proof. Draw... | |
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The line joining the midpoints of two sides of a triangle is parallel to the third side and equal to one-half of it. 
