A School Geometry, Parts 1-4Macmillan and Company, 1908 |
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Page 15
... fall along OD . 10. A straight line AOB is drawn on paper , which is then folded about O , so as to make OA fall along OB ; shew that the crease left in the paper is perpendicular to AB . ON TRIANGLES 1. Any portion of a plane surface ...
... fall along OD . 10. A straight line AOB is drawn on paper , which is then folded about O , so as to make OA fall along OB ; shew that the crease left in the paper is perpendicular to AB . ON TRIANGLES 1. Any portion of a plane surface ...
Page 18
... falls along DE , and the BAC = the EDF , .. AC must fall along DF . And because AC = DF , .. the point C must coincide with the point F. Then since B coincides with E , and C with F , .. the side BC must coincide with the side EF ...
... falls along DE , and the BAC = the EDF , .. AC must fall along DF . And because AC = DF , .. the point C must coincide with the point F. Then since B coincides with E , and C with F , .. the side BC must coincide with the side EF ...
Page 20
... fall along AC . And since AB = AC , B must fall on C , and consequently DB on DC . .. the ABD will coincide with the ACD , and is therefore equal to it . Q.E.D. COROLLARY 1. If the equal sides AB , AC of 20 GEOMETRY .
... fall along AC . And since AB = AC , B must fall on C , and consequently DB on DC . .. the ABD will coincide with the ACD , and is therefore equal to it . Q.E.D. COROLLARY 1. If the equal sides AB , AC of 20 GEOMETRY .
Page 23
... fall on B ' , and B on C ' . In Theorem 6 , on applying C to B ' and B to C ' we find that A will fall on A ' . In either case the given triangle reversed will coincide with its own " trace , " so that the side and angle on the left are ...
... fall on B ' , and B on C ' . In Theorem 6 , on applying C to B ' and B to C ' we find that A will fall on A ' . In either case the given triangle reversed will coincide with its own " trace , " so that the side and angle on the left are ...
Page 24
... falls on so that A is on the ABC to the △ DEF , E , and BC along EF , and side of EF opposite to D. Then because BC EF , C must fall on F. = Let GEF be the new position of the Join DG . Because ED EG , = EDG = the EGD . Again , because ...
... falls on so that A is on the ABC to the △ DEF , E , and BC along EF , and side of EF opposite to D. Then because BC EF , C must fall on F. = Let GEF be the new position of the Join DG . Because ED EG , = EDG = the EGD . Again , because ...
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Common terms and phrases
adjacent angles altitude angle equal base BC bisector bisects circle of radius circle whose centre circles which touch circum-circle circumference circumscribed coincide common tangents concyclic Construct a triangle COROLLARY diagonals diagram diameter distance divided draw a circle equal in area equidistant escribed circles Euclid exterior angles Find the area find the locus given angle given circle given point given straight line given triangle greater Hence hypotenuse inches inscribed isosceles triangle length Let ABC meet metres middle point millimetre nine-points circle opposite sides orthocentre parą parallelogram pedal triangle perp perpendicular PROBLEM produced Proof radii rect rectangle rectangle contained rectilineal figure required to prove respectively rhombus right angles right-angled triangle segment shew shewn straight line drawn tangent Theor Theorem trapezium triangle ABC triangles are equal vertex vertical angle
Popular passages
Page xi - IF two triangles have two angles of one equal to two angles of the other, each to each ; and one side equal to one side, viz. either the sides adjacent to the equal...
Page 44 - All the interior angles of any rectilineal figure, together with four right angles, are equal to twice as many right angles as the figure has sides.
Page 190 - Upon a given straight line to describe a segment of a circle, which shall contain an angle equal to a given rectilineal angle.
Page 12 - If, at a point in a straight line, two other straight lines, upon the opposite sides of it, make the adjacent angles together equal to two right angles, these two straight lines shall be in one and the same straight line.
Page 5 - A diameter of a circle is a straight line drawn through the centre, and terminated both ways by the circumference.
Page 122 - The square described on the hypothenuse of a rightangled triangle is equal to the sum of the squares described on the other two sides.
Page 28 - If one side of a triangle be produced, the exterior angle is greater than either of the interior opposite angles.
Page x - If two triangles have the three sides of the one equal to the three sides of the other, each to each, the triangles are congruent.
Page 65 - The sum of the perpendiculars from any point within an equilateral triangle to the three sides is equal to the altitude of the triangle (Fig.