The lengths of two sides of a triangle are 11in. and 5in. What is the distance of the third side

A.4in
B.6in.
C.10in.
D.18in.

It is C. because when u have a triangle, the sum of any two sides has to be greater than the third side

in this case

11 + 5=16 > 10
5 + 10=15 > 11
11 + 10 = 21 > 11
but

11 + 4=15 < 5
11 + 6=17 < 5
11 + 18=30 < 5

5 + 4=9 < 11
5 + 6=11 = 11
5 + 18=23 < 11

1) Always eliminate answers that cannot be correct. You should know that the 2 shorter sides, when added, must be larger than the longest side. (4+ 5 = 9) NOPE (6 + 5 = 11) NOPE

2) So it has to be C or D

3) Using the formula a^2 + b^2 = c^2, substitute in the numbers 10 and then 18 . Be sure to use the LONGEST side as C

4) The equation that is equivalent on both sides is your correct answer.

Note: What do you get when you add 11 + 5 = ???? If this is not longer than 18, then you know that cannot be the solution. If you had seen this at the beginning, it would save you having to do any calculations.

A squared + B squared = C squared. C= the longest side
if you can't do this you better figure it out soon, it only get's harder