The question asks for the angle measures of an isosceles right triangle.

An isosceles right triangle has:

• Two equal angles and one 90° angle (because it is a right triangle).
• The sum of the angles in any triangle is 180°.

Since one angle is 90°, the remaining 90° is equally divided between the two other angles. Thus, each of the two equal angles is: $\frac{90^\circ}{2} = 45^\circ$

So, the correct answer is: D. 45°, 45°, and 90°

Would you like more details or have any questions? Here are some related questions to expand your understanding:

1. How can you identify an isosceles triangle from its angles?
2. What is the significance of a right triangle in trigonometry?
3. What are the properties of a 30°-60°-90° triangle?
4. How can the Pythagorean theorem apply to isosceles right triangles?
5. How do you calculate the side lengths of a 45°-45°-90° triangle?

Tip: For any right triangle, the sum of the two non-right angles must always equal 90°.