The basic rule is that the sum of any two sides must be greater than the third.
Then there are the sine and cosine rules which involve the lengths of the sides but also the angles.
The 3 sides have different lengths
A square's sides have equal lengths, and an equilateral triangle's sides also have equal lengths.
A scalene triangle has sides of different lengths while an equilateral triangle has sides of equal lengths
An EQUILATERAL triangle has all three sides the same length. An ISOSCELES triangle has two sides with the same length. A SCALENE triangle has all three sides different lengths.
If you know the lengths of the sides, you can use the cosine rule. If you have information about other aspects of the triangle, then other formulae will apply.
A scalene triangle has 3 sides of different lengths An isosceles triangle has 2 sides of equal lengths An equilateral triangle has 3 sides of equal lengths
The 3 sides have different lengths
All three sides have different lengths.
An isosceles triangle has 3 sides 2 of which are equal in lengths An equilateral triangle has 3 sides all of which are equal in lengths
A square's sides have equal lengths, and an equilateral triangle's sides also have equal lengths.
A scalene triangle has sides of different lengths while an equilateral triangle has sides of equal lengths
An EQUILATERAL triangle has all three sides the same length. An ISOSCELES triangle has two sides with the same length. A SCALENE triangle has all three sides different lengths.
If you know the lengths of the sides, you can use the cosine rule. If you have information about other aspects of the triangle, then other formulae will apply.
A right triangle * * * * * No, it is a scalene triangle.
A triangle with a right angle and different lengths for sides is a right, scalene triangle.
A SCALENE triangle has all three sides different lengths.
A triangle that has 3 sides of unequal lengths is called a scalene triangle.