Geometry
Category : 5th Class
LEARNING OBJECTIVES
This lesson will help you to:—
Real – Life Examples
QUICK CONCEPT REVIEW
An angle is a measure of a turn. It is measured in degrees (°). There are different types of angles:
Acute angle: If the measure of an angle is less than\[{{90}^{0}}\], then it is called an acute angle.
\[\angle ABC\] is an acute angle.
Right angle: If the measure of an angle is 90°, then it is called a right angle.
Amazing Facts
\[\angle ABC\] is a right angle.
Obtuse angle: If the measure of an angle is greater than\[{{90}^{0}}\], then it is called an obtuse angle.
\[\angle ABC\]is an obtuse angle.
Symmetry is when one shape becomes exactly like another if it is rotated, reflected or translated.
The vertical line in the figure above is called line of symmetry.
3D shapes have faces, edges and vertices. A net of a
3D shape is a figure which folds up to form a 3D shape.
For example:
Net of a cube folds up to form a cube.
Historical preview
Misconception/concept
Misconcept: Students tend to find more lines of symmetry than actually exist.
Concept: The line of symmetry divides the object such that it forms two parts that are mirror image of each other.
Concept: An angle of measure \[{{90}^{0}}\] is called right angle. It has nothing to do with direction.
Properties:
For example:
These are two different nets that form cubes.
GAME
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