State, true or false :
Two isosceles-right triangles are similar. 

Answer

To determine whether the statement "Two isosceles right triangles are similar" is true or false, we can analyze the properties of isosceles right triangles step by step.

### Step 1: Understand the Definition of Isosceles Right Triangles
An isosceles right triangle is a triangle that has:
- Two sides of equal length (the legs).
- One right angle (90 degrees).
- The other two angles are equal and each measures 45 degrees.

### Step 2: Identify the Angles in Isosceles Right Triangles
In any isosceles right triangle:
- The angles are always 45 degrees, 45 degrees, and 90 degrees.
- This means that regardless of the size of the triangle, the angles remain the same.

### Step 3: Apply the Criteria for Similarity
For two triangles to be similar, they must have:
- Corresponding angles that are equal.
- This can be established through the Angle-Angle (AA) criterion for similarity.

### Step 4: Conclusion on Similarity
Since all isosceles right triangles have the same angle measures (45°, 45°, 90°), we can conclude that:
- Any two isosceles right triangles will have their corresponding angles equal.

Thus, the statement "Two isosceles right triangles are similar" is **True**.

### Final Answer
**True**

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