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| Geometry |
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Sets of
Points in a Plane
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Line, a half-line and line segment
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The line segment bisector
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Angle, measurement of angles
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Complementary, supplementary,
alternate and vertically opposite angles
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Angle bisector
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Construction of angles; 60°, 30°, 90°
and 45° (degrees)
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| Line, a half-line and line segment
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| Line is a straight one dimensional geometrical figure of infinite
length. |
| Any
pair of points uniquely determine a line, of which the segment
between given points is the shortest path |
| between them. |
| The
intersection
point A is a common point of two lines. |
| A line divides a plane into two
half-planes. |
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| Two lines are called
parallel lines, if they lie in the same plane and don’t intersect. |
| The point
A
which lies on a line divides the line into the two half-lines (rays). |
| The part of a line between two points is called a
line segment. The line segment AB
is the part of the line
l. |
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| The line segment bisector
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| The line segment bisector crosses the segment through the
midpoint M, forms a right angle and each of its points is equidistant from the segment's endpoints. |
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| Angle, measurement of angles
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| Angle is the figure formed by two half-lines or rays OA and OB
(sides of an angle) sharing a common |
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endpoint O
called the vertex of the angle. An angle is signed |
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| The unit of angles measure is a degree,
1° (deg). The angle of a
full circle (perigon or complete revolution) equals 360 degrees. |
| One degree is divided by 60 minutes,
1° = 60', one minute by 60 seconds,
1' = 60". |
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| Complementary, supplementary,
alternate and vertically opposite angles
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| Complementary angles are two angles that have the common
vertex, one common side and whose sum is |
| 90 degrees. |
| A sum of
supplementary (adjacent) angles is equal to 180 degrees. |
| Any
pair of angles formed between two intersecting lines and lying
on the same side of one of them are called |
| adjacent angles.
The adjacent angles of two intersecting lines supplement each
other. |
| Two
angles having a sum of 360 degrees are called conjugate
( or explementary) angles. |
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| When two lines intersect at one point, they form four angles. The
opposite angles on the figure above are |
| called vertical angles. Vertical angles have the same measure. |
| Angles with correspondingly
parallel sides either are equal one to another, or sum of them is 180
degrees. |
| Parallel lines intersected by a transversal
(traverse) form the angles which are equal or supplementary. |
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| The angles contained between two given lines lying on opposite
sides of the transversal are called alternate |
| angles. |
| Two angles
with mutually perpendicular sides are equal or supplementary. |
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| Angle bisector
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| An
angle bisector is a straight line that divides an angle into two
equal angles. |
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| Construction of angles; 60°, 30°, 90°
and 45° (degrees)
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| Beginning
Algebra Contents |
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| Copyright
© 2004 - 2012, Nabla Ltd. All rights reserved. |
