How would I solve this short velocity problem?

Question

You swim at 5 km/hr with your body perpendicular to a stream with a current of 2 km/hr. Your actual velocity is a vector sum of the stream's velocity and your swimming velocity. Find your actual velocity.

Answer 1

Let the stream be moving from left to right or +x direction; then your bodies motion, without the moving water would be "up" in the +y direction so that your actual motion would be vectored to the right and up. You have a Pythagorean right triangle problem with vectors:
5 i + 2 j = vector velocity ==v
Then the speed you are swimming is
|v| = sqr[5^2 + 2^2] = sqr[25+4] = sqr[29]

Answer 2

v² = 5² + 2²
v² = 29
v = √29
Actual velocity = 5.39 km / h