Math 7 Chapter 3 Lesson 9: Properties of the three altitudes of a triangle 1. Summary of theory Tóm 1.1. Altitude of the triangle. In a triangle, the perpendicular segment from a vertex to the line containing the opposite side is called the altitude of that triangle. Eg: The line segment AI is an altitude of triangle ABC, also say AI is the altitude … [Read more...] about Math 7 Chapter 3 Lesson 9: Properties of the three altitudes of a triangle

# Grade 7 Math

## Math 7 Chapter 3 Lesson 8: Properties of the three perpendicular bisectors of a triangle

Math 7 Chapter 3 Lesson 8: Properties of the three perpendicular bisectors of a triangle 1. Summary of theory Tóm 1.1. The perpendicular bisector of the triangle In a triangle, the perpendicular bisector of one side is called a perpendicular bisector of that triangle. - Each triangle has three perpendicular bisectors. Comment: In an isosceles … [Read more...] about Math 7 Chapter 3 Lesson 8: Properties of the three perpendicular bisectors of a triangle

## Math 7 Chapter 3 Lesson 7: Properties of the perpendicular bisector of a line segment

Math 7 Chapter 3 Lesson 7: Properties of the perpendicular bisector of a line segment 1. Summary of theory Tóm 1.1. Properties of points on the perpendicular Theorem 1: (Forward Theorem): A point on the perpendicular bisector of a line segment is equidistant from the two endpoints of that segment. Eg: Since point M lies on the perpendicular bisector … [Read more...] about Math 7 Chapter 3 Lesson 7: Properties of the perpendicular bisector of a line segment

## Math 7 Chapter 3 Lesson 6: Properties of the three bisectors of a triangle

Math 7 Chapter 3 Lesson 6: Properties of the three bisectors of a triangle 1. Summary of theory Tóm 1.1. The bisector of the triangle In triangle ABC, the bisector of angle A intersects side BC at point M. The line segment AM is called the bisector of triangle ABC. The line AM is also called the bisector of triangle ABC. Each triangle has three … [Read more...] about Math 7 Chapter 3 Lesson 6: Properties of the three bisectors of a triangle

## Math 7 Chapter 3 Lesson 5: The property of the bisector of an angle

Math 7 Chapter 3 Lesson 5: The property of the bisector of an angle 1. Summary of theory Tóm 1.1. Theorem 1 (forward theorem) A point on the bisector of an angle is equidistant from the sides of that angle. Eg: We have: 1.2. Theorem 2 (inverse theorem) A point inside an angle and equidistant from the sides of the angle lies on the bisector of … [Read more...] about Math 7 Chapter 3 Lesson 5: The property of the bisector of an angle

## Math 7 Chapter 3 Lesson 4: Properties of the three medians of a triangle

Math 7 Chapter 3 Lesson 4: Properties of the three medians of a triangle 1. Summary of theory Tóm 1.1. The median of the triangle - The line segment AM opposite vertex A of triangle ABC and midpoint M of side BC is called the median line (from vertex A or corresponding to side BC) of triangle ABC. The line AM is also called the median of triangle … [Read more...] about Math 7 Chapter 3 Lesson 4: Properties of the three medians of a triangle

## Math 7 Chapter 3 Lesson 3: Relationship between the three sides of a triangle Triangle inequality

Math 7 Chapter 3 Lesson 3: Relationship between the three sides of a triangle Triangle inequality 1. Summary of theory Tóm 1.1. Triangle inequality Theorem: In a triangle, the sum of the lengths of any two sides is always less than the length of the other side. Eg: Given triangle ABC, we have the following inequalities: AB + AC > BC or b + c > … [Read more...] about Math 7 Chapter 3 Lesson 3: Relationship between the three sides of a triangle Triangle inequality

## Math 7 Chapter 3 Lesson 2: Relationship between perpendiculars and oblique lines, oblique lines and projections

Math 7 Chapter 3 Lesson 2: Relationship between perpendiculars and oblique lines, oblique lines and projections 1. Summary of theory Tóm 1.1. Perpendicular line, oblique line, projection of oblique line. From point A not on line d, draw a line perpendicular to d at H. Take any point B on line d other than point H. Then: The line segment AH is … [Read more...] about Math 7 Chapter 3 Lesson 2: Relationship between perpendiculars and oblique lines, oblique lines and projections

## Math 7 Chapter 3 Lesson 1: The relationship between the angle and the opposite side in a triangle

Math 7 Chapter 3 Lesson 1: The relationship between the angle and the opposite side in a triangle 1. Summary of theory Tóm Theorem 1: In a triangle, the angle opposite the larger side is the larger angle. Example 1: Triangle ABC if AC > AB then \(\widehat B > \widehat C\) Theorem 2: In a triangle, the side opposite the larger angle is the larger … [Read more...] about Math 7 Chapter 3 Lesson 1: The relationship between the angle and the opposite side in a triangle

## Math 7 Chapter 2 Lesson 8: Congruent cases of right triangles

Math 7 Chapter 2 Lesson 8: Congruent cases of right triangles 1. Summary of theory Tóm 1.1. Known congruent cases of two right triangles - If the two right-angled sides of one right triangle are equal to the two sides of the other triangle, then the two right triangles are congruent (cgc). - If a right angled side and an adjacent acute angle of one … [Read more...] about Math 7 Chapter 2 Lesson 8: Congruent cases of right triangles