Which best explains whether a triangle with side lengths 2 in., 5 in., and 4 in. is an acute triangle?

A. The triangle is acute because [tex]$2^2 + 5^2 \ \textgreater \ 4^2$[/tex].
B. The triangle is acute because [tex]$2 + 4 \ \textgreater \ 5$[/tex].
C. The triangle is not acute because [tex]$2^2 + 4^2 \ \textless \ 5^2$[/tex].
D. The triangle is not acute because [tex][tex]$2^2 \ \textless \ 4^2 + 5^2$[/tex][/tex].



Answer :

To determine whether the triangle with side lengths 2 inches, 5 inches, and 4 inches is acute, we need to check the relationship between the squares of its side lengths.

For a triangle to be acute, the sum of the squares of any two sides must be greater than the square of the third side for all combinations:

1. First Combination: Checking [tex]\(2^2 + 4^2\)[/tex] and [tex]\(5^2\)[/tex]:
- [tex]\(2^2 = 4\)[/tex]
- [tex]\(4^2 = 16\)[/tex]
- [tex]\(5^2 = 25\)[/tex]
- Sum of squares: [tex]\(2^2 + 4^2 = 4 + 16 = 20\)[/tex]

Here, [tex]\(2^2 + 4^2 = 20\)[/tex] is less than [tex]\(5^2 = 25\)[/tex], which means this combination does not support the triangle being acute.

Given this check, the statement that best explains the triangle being acute or not is:
- "The triangle is not acute because [tex]\(2^2 + 4^2 < 5^2\)[/tex]."

Thus, the correct answer is:

The triangle is not acute because [tex]\(2^2 + 4^2 < 5^2\)[/tex].