Geometry

Question Analysis:
This question involves the angles in an isosceles right triangle.
The main focus is on using isosceles triangle properties and the triangle sum theorem.

Key Concept Explanation:
An isosceles right triangle is a right triangle where two sides are equal.
The right angle measures 90∘.
The sum of all angles in any triangle is always 180∘.

Step-by-Step Solution:
Since the two base angles are equal, we solve for them:
x + x + 90∘ = 180∘
2x = 90∘
x = 45∘

Common Mistakes:
Confusing isosceles right triangles with 30-60-90 triangles.
Forgetting that base angles in an isoscel...