This is a lowest common multiple question.
to find the lowest common multiple, you need to find the prime factors of the two numbers:


Take out duplicates:

and multiply them together:

and that is your answer.
Easy peasy.
It's exactly 4 meters because the question is asking how far below is it from the surface of the water.
B yes both triangles have an obtuse angle
$14.58
-$0.17
$14.41
÷6
2.4016666667
$2.40 per cone (rounded by cent)
For this there is no exact square root but the closest it get is about 75.33