# Math 8

## Math 8 Chapter 2 Lesson 3: Area of ​​a triangle

Math 8 Chapter 2 Lesson 3: Area of ​​a triangle 1. Theoretical Summary 1.1. Theorem The area of ​​a triangle is half the product of one side and its height. ({rm{S = }}frac{1}{2}{ah}) 1.2. Consequences The area of ​​a right triangle is half the product of the two sides of the right angle. ({rm{S = …

## Math 8 Chapter 2 Lesson 1: Polygon – Regular Polygon

Math 8 Chapter 2 Lesson 1: Polygon – Regular Polygon 1. Theoretical Summary 1.1. Polygon concept Define: A convex polygon is a polygon that always lies in a half-plane whose border is a line containing any side of the polygon. 1.2. Polygons Define: A regular polygon is a polygon with all sides equal and all …

## Math 8 Chapter 2 Lesson 2: Area of ​​a rectangle

Math 8 Chapter 2 Lesson 2: Area of ​​a rectangle 1. Theoretical Summary 1.1. The concept of polygon area The measure of a portion of the plane bounded by a polygon is called the area of ​​the polygon. Each polygon has a defined area. Polygonal area is a positive number. The area of ​​a polygon …

## Math 8 Chapter 1 Lesson 11: Rhombus

Math 8 Chapter 1 Lesson 11: Rhombus 1. Theoretical Summary 1.1. Define A rhombus is a quadrilateral with four equal sides. Eg: A rhombus ABCD has four sides AB = BC = CD = AD. – From this definition, we deduce: A rhombus is a parallelogram with two congruent adjacent sides. 1.2. Nature – Since …

## Math 8 Chapter 1 Lesson 12: Square

Math 8 Chapter 1 Lesson 12: Square 1. Theoretical Summary 1.1. Define A square is a quadrilateral with four right angles and four equal sides. From this definition we deduce: A square is a rectangle with two congruent adjacent sides. A square is a rhombus with a right angle. 1.2. Nature Since a square is …

## Math 8 Chapter 4 Lesson 9: Volume of a regular pyramid

Math 8 Chapter 4 Lesson 9: Volume of a regular pyramid 1. Summary of theory Formula for volume: The volume of a regular pyramid is one third the area of ​​the base times the height (V = dfrac{1}{3} .Sh) (S): bottom area (h): height 2. Illustrated exercise 2.1. Exercise 1 Figure 129 is a student …

## Math 8 Review chapter 4: Vertical prism. Regular pyramid

Math 8 Review chapter 4: Vertical prism. Regular pyramid 1. Summary of theory 1.1. Rectangular Define: A rectangular box is a space shape with 6 faces that are all rectangles. A rectangular box has 6 faces, 8 vertices, and 12 edges. The two faces facing each other are considered to be the base of the …

## Math 8 Chapter 4 Lesson 6: Volume of a vertical prism

Math 8 Chapter 4 Lesson 6: Volume of a vertical prism 1. Summary of theory Formula for volume The volume of a vertical prism is equal to the area of ​​the base times the height (V = S. h) (S): bottom area (h): height 2. Illustrated exercise 2.1. Exercise 1 Observe the vertical prisms in …

## Math 8 Chapter 4 Lesson 7: Regular pyramids and regular truncated pyramids

Math 8 Chapter 4 Lesson 7: Regular pyramids and regular truncated pyramids 1. Summary of theory 1.1. Pyramid – The base is a polygon, the sides are triangles that share a vertex. The line that passes through the top and is perpendicular to the plane of the base is called the altitude. 1.2. Regular pyramid …

## Math 8 Chapter 4 Lesson 8: Area around a regular pyramid

Math 8 Chapter 4 Lesson 8: Area around a regular pyramid 1. Summary of theory We usually use the following formulas: – The perimeter of a regular pyramid is equal to the product of the semicircle of the base and the midpoint. ({S_{xq}} = pd) (p is the half circumference of the base; d is …