The hypotenuse of a [tex]$45^{\circ}-45^{\circ}-90^{\circ}$[/tex] triangle measures 18 cm. What is the length of one leg of the triangle?

A. [tex]$9$ cm[/tex]
B. [tex]$9 \sqrt{2}$ cm[/tex]
C. [tex]$18$ cm[/tex]
D. [tex]$18 \sqrt{2}$ cm[/tex]



Answer :

Sure, let's solve this step by step!

In a 45°-45°-90° triangle, we know that the lengths of the legs are equal, and each leg is related to the hypotenuse by a specific ratio. The specific relationship between the side length and the hypotenuse in a 45°-45°-90° triangle is given by the formula:
[tex]\[ \text{leg} = \frac{\text{hypotenuse}}{\sqrt{2}} \][/tex]

Given that the hypotenuse measures 18 cm, we can calculate the length of one leg as follows:

1. Determine the formula application:
The length of each leg in a 45°-45°-90° triangle can be calculated using the formula:
[tex]\[ \text{leg} = \frac{18 \, \text{cm}}{\sqrt{2}} \][/tex]

2. Perform the division:
[tex]\[ \text{leg} = \frac{18}{\sqrt{2}} \][/tex]

3. Simplify the expression:
Mathematically simplifying the division can yield more insight into the exact relationship and confirm if it's written in the simplest form. Normally, multiplying numerator and denominator by \(\sqrt{2}\) would help rationalize:
[tex]\[ \text{leg} = \frac{18 \sqrt{2}}{2} = 9 \sqrt{2} \][/tex]

4. Calculate the numerical value:
Numerically evaluating the expression \(\frac{18}{\sqrt{2}}\) gives approximately 12.73 cm (not necessarily needing to reference the straightforward result).

Based on the calculations, the answer out of the options given is [tex]\(9 \sqrt{2} \, \text{cm}\)[/tex].