Fold a rectangular sheet of paper, then draw a line along the fold created. Name and compare the angles formed between the fold and the sides of the paper. Make different angles by folding a rectangular sheet of paper and compare the angles. Which is the largest and smallest angle you made?
When a rectangular sheet is folded, the crease creates angles with the sides of the paper.
Comparison Method: Angles can be compared by superimposition (placing one angle over another with vertices overlapping).
Angle Sizes:
- Largest angle: Close to a straight angle (180°)
- Smallest angle: Close to 0°
Types of Folds:
- A fold perpendicular to the sides creates right angles (90°).
- A slanted fold creates acute and obtuse angles.
Explanation
The chapter discusses comparing angles by superimposition: 'Any two angles can be compared by placing them one over the other, i.e., by superimposition. While superimposing, the vertices of the angles must overlap.' When folding paper at different angles, students can compare the angles formed by placing one angle over another. The fold perpendicular to the edges creates four right angles. Slanted folds create two acute and two obtuse angles.
Solution Steps
Fold a rectangular sheet of paper to create a crease.
Draw a line along the fold created.
Compare the angles formed between the fold and the sides by superimposition.
Observe that different folds create different angles.
Note that perpendicular folds create right angles (90°).
Note that slanted folds create acute and obtuse angles.
Identify the largest angle (close to 180°) and smallest angle (close to 0°).