Geometry

Question Analysis:
This question tests understanding of dual classification (both angles and sides).
The main focus is identifying a triangle that is right-angled and isosceles.

Key Concept Explanation:
A right isosceles triangle has: One 90° angle.
Two equal sides (legs) and two equal angles (45° each).

Step-by-Step Solution:
Option A: Angles = 45°, 45°, 90° → Right (90°) and isosceles (two equal angles).
Option B: 3-4-5 is right but scalene (all sides unequal).
Option C: 60°-60°-60° is equilateral, not right.
Option D: 5-5-7 is isosceles but not right.

Option Analysis:
A) Correct: Fi...