If the angles of a triangle are [tex]$45^{\circ}, 45^{\circ}$[/tex], and [tex]$90^{\circ}$[/tex], show that the length of the hypotenuse is [tex][tex]$\sqrt{2}$[/tex][/tex] times as long as each leg.

1. Substitute the side lengths of the triangle into the Pythagorean theorem.

[tex]a^2 + a^2 = c^2[/tex]

2. Combine like terms.

[tex]2a^2 = c^2[/tex]

3. Solve for [tex]c[/tex].

[tex]c = a\sqrt{2}[/tex]



Answer :

Let's walk through the steps to show that the length of the hypotenuse in a right-angled isosceles triangle is [tex]$\sqrt{2}$[/tex] times the length of each leg:

Step 1: Understand the triangle type and side lengths

Given a triangle with angles [tex]$45^\circ$[/tex], [tex]$45^\circ$[/tex], and [tex]$90^\circ$[/tex], this is a right-angled isosceles triangle. In such triangles, the two leg lengths are equal. Let each leg have length [tex]$a$[/tex].

Step 2: Apply the Pythagorean theorem

In a right triangle, the Pythagorean theorem states:
[tex]\[ a^2 + b^2 = c^2 \][/tex]
Since both legs are of equal length [tex]$a$[/tex], the equation becomes:
[tex]\[ a^2 + a^2 = c^2 \][/tex]

Step 3: Combine like terms

Combine the terms on the left-hand side:
[tex]\[ 2a^2 = c^2 \][/tex]

Step 4: Solve for the hypotenuse [tex]\(c\)[/tex]

To find [tex]\(c\)[/tex], we take the square root of both sides:
[tex]\[ c = \sqrt{2a^2} \][/tex]
[tex]\[ c = a\sqrt{2} \][/tex]

This shows that the hypotenuse [tex]\(c\)[/tex] is [tex]\(\sqrt{2}\)[/tex] times the leg length [tex]\(a\)[/tex]. Therefore, the length of the hypotenuse is indeed [tex]\(\sqrt{2}\)[/tex] times the length of each leg in such a triangle.

Hence, if the leg length is [tex]\(a\)[/tex], then the hypotenuse [tex]\(c\)[/tex] evaluates numerically as [tex]\(1.4142135623730951\)[/tex] (when [tex]\(a = 1\)[/tex]), which is equivalent to [tex]\(\sqrt{2}\approx 1.4142135623730951\)[/tex].