Question

Which of the following can not be the three lengths of the sides of a triangle?
A. 120, 85, 220
B. 70, 60, 120
C. 45, 50, 80
D. 130, 70, 190

Answer 1

The sum of the lengths of any two sides of a trinalge must be greater than the lengh of the third side.

For each group of 3 lengths (each choice A, B, C, and D), take the lengths 2 at a time and add them. If in all 3 cases, the sum of two lengths is greater than the third length, that is a possible triangle.

Answer 2

i want to eliminate D, and A

Answer 3

Let's do C. together as an example:
C. 45, 50, 80
Is 45 + 50 > 80? 95 > 80 is true.
Is 45 + 80 > 50? 125 > 50 is true.
Is 50 + 80 > 45? 130 > 45 is true.
Since all 3 pairs of lengths added together are greater than each third length, choice C is a possible triangle.

Answer 4

Do the above to choices A, B, and D.

Answer 5

A

Answer 6

Remember you're looking fo the choice that does NOT give a triangle.

Answer 7

Correct.
120 + 85 = 205, and 205 is not greater than 220, so A is not a triangle.