Question

Which set of sides will make a triangle?

-Middle School math-

Answer 1

Hey there!

The biggest side in the set of 3 lengths needs to be lower than the sum of the two lower numbers. So 3 is not lower than 1+1. 10 is not less than 3+4. 5 is the same as 3+2. This is not possible because this makes a line. So the biggest side can’t equal the sum of the two lower sides. 10 is less than 5+9. So the answer would be the last one. 10 cm, 5 cm, 9 cm.

I hope this helps!

Answer 2

Answer: 10 cm, 5 cm, 9 cm

In order to make a triangle, the sum of the two shorter side lengths must be greater than the length of the longest side.

5, 2, 3    ⇒    5 = 5    ⇒    not a triangle
1, 3, 1      ⇒    2 < 3    ⇒    not a triangle
10, 3, 4   ⇒    7 < 10   ⇒    not a triangle