Class 7 Mathematics Chapter 6 | The Triangle And Its Properties TextBook Solutions And Practice Sums
* The six elements of a triangle are its three angles and the three sides.
* The line segment joining a vertex of a triangle to the midpoint of its opposite side is called a median of the triangle. A triangle has 3 medians.
* The perpendicular line segment from a vertex of a triangle to its opposite side is called an altitude of the triangle. A triangle has 3 altitudes.
* An exterior angle of a triangle is formed, when a side of a triangle is produced.
* Exterior Angle Sum Property:
The measure of any exterior angle of a triangle is equal to the sum of the measures of its interior opposite angles.
The Angle Sum Property of a triangle:
The total measure of the three angles of a triangle is 180.
* A triangle is said to be equilateral, if each one of its sides has the same length.
In an equilateral triangle, each angle has measure 60.
* A triangle is said to be isosceles, if at least any two of its sides are of same length.
* The sum of the lengths of any two sides of a triangle is greater than the length of the third side.
*The difference between the lengths of any two sides is smaller than the length of the third side.
* In a right angled triangle, the side opposite to the right angle is called the hypotenuse and the other two sides are called its legs.
In a right-angled triangle,
The square on the hypotenuse = the sum of the squares on its legs.