### Home > A2C > Chapter 4 > Lesson 4.2.4 > Problem 4-126

4-126.

Use the Pythagorean Theorem.

*x* = ± 21

Use the positive side length.

See part (a).

You can use special triangles 30-60-90 and 45-45-90, or solve by using the Law of Sines.

*x* = 50 Remember to check your work.