- A flat surface is called a plane.
- Infinite number of points can be marked on a plane.
- A straight line that has no end points is called a line.
- A straight line that has one end point is called a ray.
- A straight line that has two end points is called a segment.
- When two rays meet at a common point called the vertex, an angle is formed.
- An angle that measures 90 degrees is called a right angle.
- An angle that measures less than 90 degrees is called acute angle.
- An angle that measures more than 90 degrees is called obtuse angle.
- Two lines that cross through each other are called intersecting lines.
- Two lines that form 90 degrees on intersection are called perpendicular lines.
- Two lines that do not intersect each other at any point are called parallel lines.
- A line segment that extends from the center of a circle to a point on the circle is called radius.
- A line segment that has two of the end points on the circle is called the diameter.
Directions: Answer the following questions. Also draw a ray, line, segment, acute angle, obtuse angle, right angle, parallel lines, perpendicular lines, intersecting lines, circle with radius and diameter.
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