6 Form PACE WORK 27/04/20
Тема: П’ятикутник
In t
- What geometric figures do you know?
- Draw them.
1. Circle
2. Line
3. Rectangle
4. Triangle
5. Square
IV. Основна частина уроку.
4.1. Revision.
Is it a Pentagon?
A pentagon has 5 straight sides. The shape must also be closed (all the
lines connect up):
A pentagon is a 5-sided Polygon (a flat shape with straight sides):
Regular or Irregular
When all angles are equal and all sides are equal it is regular,
otherwise it is irregular:
regular irregular
Concave or Convex
A convex pentagon has no angles pointing inwards. More precisely, no
internal angles can be more than 180°.
When any internal angle is greater than 180° it is concave. (Think:
concave has a "cave" in it)
Properties
A regular pentagon has:Interior Angles of 108°
Exterior Angles of 72°
Area of approximately 1.7204774 × s2 (where s=side length)
Draw a regular pentagon.
Draw an irregular pentagon.
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