Geometry: Shapes & Angles

2D shapes, angles and their properties

Explore 2D shapes, types of angles, and the properties of triangles and polygons.

✓ Acute < 90° < Right = 90° < Obtuse < 180...✓ Angles on a straight line add to 180°✓ Angles at a point add to 360°

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📖 Understanding Geometry: Shapes & Angles

Geometry is the study of shapes, sizes and spaces. A point has no size. A line extends infinitely in both directions. A line segment has two endpoints.

An angle is formed when two rays meet at a point (vertex). Angles are measured in degrees (°). A full rotation is 360°.

Types of angles: Acute (less than 90°), Right (exactly 90°), Obtuse (between 90° and 180°), Straight (180°), Reflex (between 180° and 360°).

In any triangle, the three angles always add up to 180°. In any quadrilateral, the angles add up to 360°. For any polygon with n sides, interior angles sum = (n−2) × 180°.

🔑 Key Points to Remember

✓Acute < 90° < Right = 90° < Obtuse < 180°
✓Angles on a straight line add to 180°
✓Angles at a point add to 360°
✓Triangle angles sum = 180°
✓Quadrilateral angles sum = 360°

#geometry#angles#shapes#triangles#middle school

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🔗 Related Topics

📏Area & Perimeter 🔺Trigonometry