Question

Eva has four sets of straws.
The measurements of the straws are given below.
Which set of straws could not be used to form a triangle?
Select one:

A.set 1: 4 cm, 4 cm, 7 cm

B.set 2: 2 cm, 3 cm, 8 cm

C.set 3: 3 cm, 4 cm, 5 cm

D.set 4: 5 cm, 12 cm, 13 cm

Answer 1

D

You need to use trigonometry, and square all of the numbers, you then add the lowest two and they should sum to the other number.

The set that this works for is the correct set.

Hope this helps x

Answer 2

Set D, Pythagorean theory
Side 1 sq + side 2 sq = side 3 sq
5sq + 12sq = 13sq
25 + 144 = 169