Answer: The boats are 44.82 miles from each other.
Step-by-step explanation:
The direction of movement of Marcus and Sandra forms a right angle triangle.
The distance sailed by Marcus due North would represent the opposite side of the right angle triangle.
The distance sailed by Sandra due east would represent the adjacent side of the right angle triangle.
The distance, h between the both of them after 2 hours represents the hypotenuse of the right angle triangle.
To determine h, we would apply Pythagoras theorem which is expressed as
Hypotenuse² = opposite side² + adjacent side²
h² = 35² + 28² = 1225 + 784
h² = 2009
h = √2009
h = 44.82 miles