The question asks for a true statement about a 45°-45°-90° triangle, which is a special right triangle.

In a 45°-45°-90° triangle, the legs are congruent, and the hypotenuse is always √2 times the length of either leg. This is derived from the Pythagorean Theorem, where for such triangles, if each leg has length x, the hypotenuse has length x√2.

Thus, the correct answer is A: The hypotenuse is √2 times as long as either leg.

Would you like further details on how the properties of a 45°-45°-90° triangle are derived, or do you have other questions?

Here are some related questions for deeper understanding:

1. How do we derive the relationship between the legs and hypotenuse in a 45°-45°-90° triangle?
2. What is the Pythagorean Theorem, and how is it applied to right triangles?
3. How do the side ratios differ between a 45°-45°-90° triangle and a 30°-60°-90° triangle?
4. Can we use trigonometric functions to find angles in a 45°-45°-90° triangle?
5. How can a 45°-45°-90° triangle be applied in real-world problems?

Tip: Always remember that in a 45°-45°-90° triangle, both legs are equal, and the hypotenuse is √2 times the length of a leg.