Answer:
x = 11√2
Explanation:
This is a special right triangle. It is marked with a small box in one angle. That is a right angle. So it is a right triangle. It is also marked on two sides with a single hash mark to show that those two sides are the same. This means that the two smaller angles are the same. This is a 45°-45°-90° triangle.
A 45°-45°-90° triangle has a special pattern for knowing the sides of the triangle. One leg is given that it is 11. So the other leg is also 11. Then you could use Pythagorean theorem to find x. But there is a short cut!
Because this is a 45°-45°-90° triangle the hypotenuse (the long side) is:
hypotenuse = leg√2
hypotenuse = 11√2
x = 11√2
This is a handy shortcut, it works for all 45°-45°-90° triangles.