CPM Homework Help : CC3MN Problem 9-12

What kind of triangle will the edges of the squares at right form? What will the side lengths be?

Hint:

Here are the squares reproduced below.
What kind of triangle do these form?

3 squares of different sizes. 1 side from each square is connected at the vertex of another square to form an interior obtuse triangle.

Answer:

How do you know it is an obtuse triangle without looking at the picture?
How can you find the side lengths from the areas of the squares?

3 squares labeled as follows: 36 square units, 400 squares, and 625 square units.