- A point is simply a location.
- A line is made up of points and has no thickness or width. Points on the same line are said to be collinear.
- A plane is a flat surface made up of points. Points that lie on the same plane are said to be coplanar. A pane has no depth and extends infinitely in all directions.
- Points are often used to name lines and planes.
- Midpoint of a line segment is the point on the segment that divides the segment into two congruent segments. If B is the midpoint of line AC, then AB = BC.
- Ray is part of line. It has one endpoint and extends indefinitely in one direction.
- Angle is formed by two non collinear rays that have a common endpoint. The rays are called sides of the angle. The common endpoint is the vertex.
- An angle divides a plane into three distinct parts: points on the angle, interior of the angle and exterior of the angle.
- Kinds of Angles:
- Acute Angle: An angle whose measure is less than 90 degrees and greater then zero degrees is called an acute angle.
- Right Angle: An angle whose measure is 90 degrees is called right angle.
- Obtuse Angle: An angle whose measure is greater than 90 degrees and less than 180 degrees is called obtuse angle.
- Straight Angle: An angle whose measure is 180 degrees called a straight angle.
- Reflex Angle: An angle whose measure is greater than 180 degrees and less than 360 degrees is called a reflex angle.
- Complete Angle: An angle whose measure is 360 degrees is called a complete angle.
- Zero Angle: If the measure of an angle is zero it is called a zero angle.
- Complementary Angles: Two angles are said to be complementary if the sum of their measure is 90o.
- Supplementary Angles: Two angles are said to be supplementary if the sum of their measure is 180o.
- Adjacent Angles: Two angles in a planes are called adjacent angles, if they have a common vertex, a common side, and their interiors do not have a common point. Angles 1 and 2 below are adjacent angles.
- Adjacent Angles: Two angles in a planes are called adjacent angles, if they have a common vertex, a common side, and their interiors do not have a common point. Angles 1 and 2 below are adjacent angles.
- Linear Pair of Angles: A pair of adjacent angles formed by intersecting lines is called a Linear Pair of Angles.
- Vertically Opposite Angles: When two lines intersect, then the angles that are opposite one another at the intersection are called Vertically Opposite Angles. The measures of the vertically opposite angles are equal.
Directions: For each of the above points draw an explain in your own words. Choose the correct answers.
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