Question

Input the length of three sides and check if they can form a triangle

Answer 1

The triangle inequality rule, which states: the length of a side of a triangle is less than the sum of the lengths of the other two sides and greater than the difference of the lengths of the other two sides.

Let's say that a, b, c is the sides of the triangle. Therefore, it must be satisfy this criteria :

   a + b > c

   a + c > b

   b + c > a

Check whether it is possible to have a triangle with the given side lengths.

7,9,13

Add any two sides and see if it is greater than the other side.

The sum of 7 and 9 is 16 and 16 is greater than 13

The sum of 9 and 13 is 21 and 21 is greater than 7

The sum of 7 and 13 is 20 and 20 is greater than 9

This set of side lengths satisfies the Triangle Inequality Theorem.

∴These lengths do form a triangle.