Concise Selina Solutions for Class 9 maths Chapter 11 Inequalities

Triangle elements like sides, angles, areas etc. are bound by inequalities, foremost of which is the Triangle Inequality. The triangle inequality theorem is very useful when one needs to determine if any 3 given sides will form of a triangle or not.

The triangle inequality states that for any triangle, the sum of the lengths of any two sides must be greater than or equal to the length of the remaining side. If x, y, and z are the lengths of the sides of the triangle, with no side being greater than z, then the triangle inequality states that z = x + y. We shall learn the other theorems related to inequalities in this topic.

Many simple inequalities can be solved by adding, subtracting, multiplying or dividing both sides until you are left with the variable on its own. But these things will change the direction of the inequality: Multiplying or dividing both sides by a negative number, swapping left and right-hand sides.