JC walks 6 meters East and 5 meters North. What is the magnitude of his total displacement in meters?

Can someone explain to me how to do this problem ?

Waves are used in many practical applications to support work, entertainment, and health. one example is the use of ultrasound imaging to safely track the development of a growing fetus. what is a specific example of a practical application of waves in medicine, entertainment, safety, or other fields? provide a brief explanation of how the properties of waves are useful to that application.

Does current flow through or across a resistor?