Which best explains whether a triangle with side lengths [tex]$5 \, \text{cm}$[/tex], [tex]$13 \, \text{cm}$[/tex], and [tex]$12 \, \text{cm}$[/tex] is a right triangle?

A. The triangle is a right triangle because [tex]$5^2 + 12^2 = 13^2$[/tex].
B. The triangle is a right triangle because [tex]$5 + 13 \ \textgreater \ 12$[/tex].
C. The triangle is not a right triangle because [tex]$5^2 + 13^2 \ \textgreater \ 12^2$[/tex].
D. The triangle is not a right triangle because [tex]$5 + 12 \ \textgreater \ 13$[/tex].



Answer :

First, let's understand what it means for a triangle to be a right triangle. A triangle is a right triangle if it satisfies the Pythagorean theorem, which states [tex]\( a^2 + b^2 = c^2 \)[/tex], where [tex]\( c \)[/tex] is the hypotenuse (the longest side of the triangle) and [tex]\( a \)[/tex] and [tex]\( b \)[/tex] are the other two sides.

Given the side lengths: [tex]\( 5 \, \text{cm} \)[/tex], [tex]\( 13 \, \text{cm} \)[/tex], and [tex]\( 12 \, \text{cm} \)[/tex]:

1. Identify the longest side, which will be the hypotenuse ([tex]\( c \)[/tex]). In this case, it is [tex]\( 13 \, \text{cm} \)[/tex].

2. Use the Pythagorean theorem to check if the given sides satisfy the condition:
[tex]\[ a^2 + b^2 \stackrel{?}{=} c^2 \][/tex]
Here, [tex]\( a = 5 \, \text{cm} \)[/tex], [tex]\( b = 12 \, \text{cm} \)[/tex], and [tex]\( c = 13 \, \text{cm} \)[/tex].

3. Calculate [tex]\( a^2 \)[/tex]:
[tex]\[ 5^2 = 25 \][/tex]

4. Calculate [tex]\( b^2 \)[/tex]:
[tex]\[ 12^2 = 144 \][/tex]

5. Calculate [tex]\( c^2 \)[/tex]:
[tex]\[ 13^2 = 169 \][/tex]

6. Add [tex]\( a^2 \)[/tex] and [tex]\( b^2 \)[/tex] to verify if the left-hand side of the equation equals the right-hand side:
[tex]\[ 25 + 144 = 169 \][/tex]

7. Since the left-hand side [tex]\( 25 + 144 \)[/tex] equals the right-hand side, [tex]\( 169 \)[/tex], we can conclude the triangle satisfies the Pythagorean theorem. Therefore, the side lengths form a right triangle.

So, the best explanation is:
The triangle is a right triangle because [tex]\( 5^2 + 12^2 = 13^2 \)[/tex].