Answer:
6.5km
Step-by-step explanation:
If you make a diagram, you'll see the submarine forms a right angle triangle with the base, where the hypotenuse is the length from the submarine to its base, and 5.5 and 3.4 are the side lengths. To find the hypotenuse, use the formula a^2+b^2=c^2.
5.5^2+3.4^=c^2
41.81=c^2
6.466=c
Round it to one decimal point and you get 6.5km.
