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# Polygonau

Cyflwyniad i bolygonau ar gyfer blwyddyn 7
Published on: Mar 4, 2016
Published in: Education      Technology

#### Transcripts - Polygonau

• 1. Polygonau Siapau Gyda Llinellau Syth
• 2. Enghreifftiau o Bolygonau
• 3. Nid yw siapau hyn yn bolygonau
• 4. Enghreifftiau o bolygonau rheolaidd – Pob ochr yr un hyd
• 5. Types of Polygons
• 6. Triangle <ul><li>A triangle has three sides. </li></ul>1 2 3
• 7. Everyday triangles…
• 8. There are several types of triangles
• 9. <ul><li>Isosceles Triangles have 2 equal sides. </li></ul><ul><li>Equilateral Triangles have 3 equal sides </li></ul><ul><li>Scalene Triangles have no equal sides </li></ul>
• 10. <ul><li>Acute triangles have 3 acute angles </li></ul><ul><li>Obtuse triangles have 1 obtuse angle </li></ul><ul><li>Right triangles have 1 right angle </li></ul>
• 12. Square <ul><li>Squares have 4 equal parallel sides and 4 right angles. </li></ul><ul><li>Squares are regular polygons </li></ul>
• 13. Everyday Squares
• 14. Rectangles <ul><li>Rectangles have parallel sides that are equal to each other. </li></ul><ul><li>All angles are right angles. </li></ul>
• 15. Everyday Rectangles
• 16. Rhombus <ul><li>A rhombus has four equal parallel sides. </li></ul>
• 17. Parallelogram <ul><li>Parallelograms have opposite equal parallel sides </li></ul>
• 18. Everyday Parallelograms
• 19. Trapezoid <ul><li>Trapezoids have one set of parallel sides. </li></ul>
• 20. Everyday Trapezoids
• 21. Pentagon <ul><li>A pentagon has five sides. </li></ul>1 2 3 4 5
• 22. Everyday Pentagons
• 23. Hexagon <ul><li>A hexagon has six sides. (Hexagon and six both have an “x”.) </li></ul>
• 24. Everyday Hexagons
• 25. Heptagon <ul><li>A heptagon has seven sides. </li></ul>
• 26. Everyday Heptagons
• 27. Octagon <ul><li>An octagon has eight sides. Count the sides. </li></ul>If this octagon was red and had the word “Stop” written on it, then you would know where we see a lot of octagons.
• 28. Everyday Octagons
• 29. Nonagons <ul><li>Nonagons have nine sides </li></ul>
• 30. Everyday Nonagons
• 31. Decagon <ul><li>Decagons have 10 sides. </li></ul>
• 32. Everyday Decagons
• 33. Hendecagon <ul><li>Hendecagons have 11 sides </li></ul>
• 34. Everyday Hendecagons
• 35. Dodecagons <ul><li>Dodecagons have 12 sides </li></ul>
• 36. Everyday Dodecagons
• 37. <ul><li>A triangle is the smallest polygon because it has three sides. Can you have a two-sided polygon? Why or why not? </li></ul>Two lines don’t close to make a shape. They make an angle. 2 1 Key Question: