Lesson 1.1 The Building Blocks of Geometry Ob jectives ·Understand and identify the undefined terms point, line, and plane. ·Define segment, angle, collinear, intersect, intersection, and coplanar. Investigate postulates about points, lines, and planes. BE LLRINGER! List examples you see in this room, or in real-life of these geometric terms Point: ____________________________ Line Segment: _____________________ Angle: ___________________________ Line: ____________________________ Plane (NOT from the sky): ___________

Vocabulary · _____________________ are often shown as dots, but unlike physical dots, geometric _______________________ have no size. Points are named by capital letters such as A or X. Example X A ·A geometric _______________ has no thickness, is perfectly straight, and extends forever. A line can be named by two points on the line, with a double-headed arrow ( ) over the two letters, or by a single lower case letter. Example

Vocabulary Continued · A geometric _________________ extends infinitely in all directions along a flat surface. You can think of any flat surface, such as the top of your desk, as representing a portion of a plane. Planes can be named by three points that lie in the plane, or a plane can be renamed by a script capital letter. What should we name this plane? _________________________ ·A ___________________ is a part of a line that begins at one point and ends at another. The points are called the ___________________ of the segment. A B · A ______________ is a part of a line that starts at a point and extends infinitely in one direction. The point is called the endpoint of the ray. XY N M O R

ANGLES AND INTERSECTIONS · An _____________ is a figure formed by two rays with a common endpoint. The common endpoint is called the vertex of the angle, and the rays are the sides of the angle. ·An angle divides a plane, into two regions: the interior and exterior of the angle. If two points, one from each side of an angle, are connected by a segment, the segment passes through the interior of the angle. ·When geometric figures have one or more points in common they are said to ___________________. The set of points that they have in common is called their _______________________. Fundamental geometry ideas, or _____________________, are statements that are accepted as true without proof. They are building blocks of geometry.

Check for Understanding Pg. 12 (1-5) Postulate T he intersection of two lines is a ___________________ Po stulate T he intersection of two planes is a _________________ Po stulate T hrough any two points there is exactly one ________________ Po stulate T hrough any three noncollinear points there is exactly one _________________________ Po stulate I f two points are in a plane then the line containing them ___________________________________

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