This document discusses angles and angle measurement. It explains that points, lines, and planes are the basic building blocks of geometry used to construct angles and shapes. Angles are usually measured in degrees, with 360 degrees making a full turn. This system of 360 degrees originated with the Babylonians, who used a base-60 number system that made fractions of degrees easy to calculate.

1. Chapter 2: Angle relationships
(Part 1)
Saumil S. Sharma
B.Sc., MBA
NSW Syllabus for the Australian Curriculum
Cambridge MATHS for Year 7

2. Points, Lines, Intervals and Angles
• The fundamental building blocks of geometry are the point,
line and plane.
• They are the basic objects used to construct angles, triangles
and other more complex shapes and objects.
• Points and lines do not actually occupy any area but can be
represented on a page using drawing equipment.

3. Points, Lines, Intervals and Angles

4. Points, Lines, Intervals and Angles

5. Points, Lines, Intervals and Angles

6. Points, Lines, Intervals and Angles

19. Measuring and classifying angles
• Angles are usually described using the unit of measurement
called the degree, where 360 degrees (360°) describes one
full turn.
• The idea to divide a circle into 360° dates back to the
Babylonians, who used a sexagesimal number system based
on the number 60. Because both 60 and 360 are numbers that
have a large number of factors, many fractions of these
numbers are very easy to calculate.

20. Measuring and classifying angles

21. Measuring and classifying angles

22. Measuring and classifying angles

23. Measuring and classifying angles

24. Measuring and classifying angles