# Which Relationship in the Triangle Must Be True?

Which Relationship in the Triangle Must Be True?

Triangles are fundamental shapes in geometry, consisting of three sides and three angles. When studying triangles, it is essential to understand the relationships between their sides and angles. One of the most important concepts in triangle relationships is the Triangle Inequality Theorem.

The Triangle Inequality Theorem states that the sum of the lengths of any two sides of a triangle must always be greater than the length of the third side. This theorem helps us understand which relationships in a triangle must be true. Let’s explore this further.

In a triangle, there are three possible relationships between the lengths of the sides:

1. Side A < Side B + Side C
2. Side B < Side A + Side C
3. Side C < Side A + Side B Out of these three relationships, at least one must be true for a triangle to exist. If any of these relationships are false, it would be impossible to form a closed figure with three sides. To illustrate this, let’s take an example: a triangle with side lengths of 5, 6, and 10. We can test the three relationships mentioned above:

1. 5 < 6 + 10 (True)
2. 6 < 5 + 10 (True)
3. 10 < 5 + 6 (True) In this case, all three relationships are true, which means this triangle is valid. However, if any of the relationships were false, the triangle would not exist. Now, let’s address some common questions related to triangle relationships: 1. Can a triangle have two sides of equal length?
Yes, a triangle can have two sides of equal length, which is called an isosceles triangle.

2. Can a triangle have three sides of equal length?
Yes, a triangle with three sides of equal length is called an equilateral triangle.

3. Can a triangle have no sides of equal length?
No, a triangle cannot have all sides of different lengths. At least two sides must be of equal length.

4. Can a triangle have two sides of equal length and one side longer?
No, if two sides of a triangle are equal in length, the third side cannot be longer than the sum of these two sides.

5. Can a triangle have two sides of equal length and one side shorter?
Yes, a triangle can have two sides of equal length and one side shorter. This is possible as long as the shorter side satisfies the Triangle Inequality Theorem.

6. Can a triangle have two sides that sum up to the same length as the third side?
No, the sum of any two sides of a triangle must be greater than the length of the third side.

7. Can a triangle have two sides that sum up to a length less than the third side?
No, the sum of any two sides of a triangle must be greater than the length of the third side.

8. Can a triangle have two sides that sum up to a length equal to the third side?
Yes, a triangle can have two sides that sum up to a length equal to the third side. This forms a degenerate triangle, which is essentially a straight line.

9. Can a triangle have one side longer than the sum of the other two sides?
No, if one side of a triangle is longer than the sum of the other two sides, the triangle cannot exist.

10. Can a triangle have one side shorter than the sum of the other two sides?
Yes, a triangle can have one side shorter than the sum of the other two sides. This is possible as long as the longer sides satisfy the Triangle Inequality Theorem.