A river flows due south with a speed of 400ms a man steers

Question

Solve the all given parts of following problem:

Problem: A river flows due south with a speed of 4.00m/s . A man steers a motorboat across the river; his velocity relative to the water is 3.80m/s due east. The river is 760m wide.

Part I: What is the magnitude of his velocity relative to the earth?

Part II: What is the direction of his velocity relative to the earth?

Part III: How much time is required for the man to cross the river?

Part IV: How far south of his starting point will he reach the opposite bank?

I need help to find the direction of his velocity relative to the earth.