# Shapes and Angles

## Overview
This chapter helps students understand shapes and the role of angles in forming them. Through practical activities using matchsticks and visual observations, students learn about open and closed shapes, different types of angles (right, smaller than right, and bigger than right), and how angles can be observed in letters and natural structures.

## Key Topics Covered

### 1. Playing with Shapes and Angles
- **Rohini and Mohini’s Activity**: Rohini creates a shape using matchsticks, and Mohini tries to replicate it by asking questions.
- **Understanding Closed and Open Shapes**:
- Closed Shape: All sides join together to form a boundary.
- Open Shape: Sides do not form a complete boundary.
- **Recognizing Sides and Angles**: The number of sides and the angles at which the sticks are joined define the shape.
- **Key Observation**: Even with the same number of sides, changing angles changes the shape entirely.

### 2. Types and Comparison of Angles
- **Angle Variations with Matchsticks**:
- When the angle is small, the shape is sharper.
- A big angle makes the shape broader.
- **Activity**: Identifying smallest and biggest angles through matchstick patterns and colored angle markings.

### 3. Equal and Unequal Angles
- Practice-based observation:
- Are angles marked with the same color equal?
- Visual recognition of angle equality through shape comparisons.

### 4. Angles in Names and Letters
- **Fun Activity**: Writing names using only straight lines and counting different types of angles:
- Number of right angles
- Number of angles less than a right angle
- Number of angles more than a right angle
- **Purpose**: Makes children observe letters as shapes and identify geometric properties in daily writing.

### 5. Practical Exploration of Angles
- **Book Slide Activity**:
- Stacking books and slanting one to create a slide.
- Rolling a ball and observing which angle makes the ball roll faster.
- **Bird Beak Observation**:
- Finding birds with beaks having smaller than right angles.
- **Tree Branch Angle Comparison**:
- Observing and comparing angles between tree branches.


## New Terms

| Term | Definition |
|--------------------------|----------------------------------------------------------------------------|
| Angle | The space between two lines or surfaces that meet at a point |
| Right Angle | An angle that forms a perfect square corner (90 degrees) |
| Less than a Right Angle | A smaller angle than a right angle (acute angle) |
| More than a Right Angle | A bigger angle than a right angle (obtuse angle) |
| Closed Shape | A shape where all sides are connected without any gap |
| Open Shape | A shape where sides do not connect fully and has a gap |
| Polygon | A closed shape made of straight lines |
| Matchsticks | Used in the chapter to form different shapes and angles |
| Slide | A sloping surface used in the activity to understand angle steepness |
| Beak | Hard pointed part of a bird's mouth; used to observe angles in nature |

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## Practice Questions

### 🟢 Easy (3 Questions)

**1.** How many right angles are there in a square?
**Answer:** 4
**Explanation:** A square has four equal corners, each being a right angle.

**2.** Which of these is an open shape?
(A) Triangle (B) Rectangle (C) An L-shaped line (D) Square
**Answer:** (C) An L-shaped line
**Explanation:** L-shape does not close all sides, so it’s an open shape.

**3.** Is an angle smaller than a right angle called an acute angle?
**Answer:** Yes
**Explanation:** Any angle less than 90° is called an acute angle.

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### 🟡 Medium (2 Questions)

**4.** Rohini made a shape with 6 matchsticks and 6 angles. What kind of shape could it be?
**Answer:** A hexagon
**Explanation:** A polygon with 6 sides and 6 angles is called a hexagon.

**5.** If two books are slanted at different angles, and a ball rolls faster on one, what does it mean?
**Answer:** The faster slide has a bigger angle.
**Explanation:** A steeper angle allows the ball to roll faster.

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### 🔴 Difficult (3 Questions)

**6.** You draw a shape with 4 sides and two of the angles are more than a right angle. Can it be a square?
**Answer:** No
**Explanation:** A square has all angles equal to 90°, no angle can be more or less.

**7.** In a name made using only straight lines, there are 3 right angles and 5 angles less than a right angle. Which letters could it include?
**Answer:** Letters like L, T, A, V
**Explanation:** These letters have straight lines and create different angles.

**8.** Why does changing the angle at the corners change the shape, even if the number of sides remains the same?
**Answer:** Because angle size affects how sides are positioned and joined.
**Explanation:** A polygon’s appearance depends on both number of sides and angle size.

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### 🔵 Very Difficult (2 Questions)

**9.** Compare two hexagons: one has all equal angles, and one has 3 big and 3 small angles. Are they the same shape?
**Answer:** No
**Explanation:** Even if both have 6 sides, unequal angles create different shapes.

**10.** In a tree diagram, the branches form angles with the trunk. One branch is at 90°, the second at 120°, and the third at 45°. Which is the smallest and which is the largest?
**Answer:** 45° is the smallest, 120° is the largest
**Explanation:** 45° < 90° < 120°, so we can compare the angles directly.

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