Find Side q in 45-45-90 Right Triangle

Published on March 12, 2026

Geometry

Determine the length of leg q in a 45-45-90 triangle where the hypotenuse is  s2, using the properties of isosceles right triangles or trigonometry.

Question

Answer

Here is the step-by-step solution to find the value of .
1. Analyze the Triangle
The image shows a triangle with the following known properties:
  • Two angles are each.
  • One angle is marked with a square, indicating it is a right angle, which means it measures .
The sum of the angles in any triangle must be . Let the third angle be .
Wait, let’s re-examine the image. The image shows two angles marked as and one angle marked as (the right angle symbol). This configuration ( ) defines a special type of right triangle: a - - triangle, which is also an isosceles right triangle.
2. Properties of a - - Triangle
In a - - triangle, the two legs (the sides opposite the angles) are equal in length.
The relationship between the leg length ( ) and the hypotenuse ( ) is:
3. Identify Sides in the Given Triangle
  • The sides opposite the angles are the legs.
  • The side opposite the angle is the hypotenuse.
From the diagram:
  • One leg is labeled .
  • The other leg is not explicitly labeled, but since it is opposite a angle, it must be equal to .
  • The side labeled is opposite the angle, so it is the hypotenuse.
Therefore, we have:
  • Leg
  • Hypotenuse
4. Set up the Equation
Using the relationship where and :
5. Solve for
To find , divide both sides by :
Alternatively, using trigonometry (SOH CAH TOA):
If we use the angle adjacent to side :
  • Side is the Adjacent side.
  • Side is the Hypotenuse (opposite the angle).
  • We use the Cosine function:
We know that .
Multiply both sides by :
The value of is . Since the answer must be in simplest radical form, is acceptable (it is or just ).
The answer is units.