Answer:
the submarine is 92.994 feet ≈ 93 feet deep from the surface of the water
Explanation:
We can think in a triangle where the hypotenuse is the detection distance and the angle with the horizontal surface of water is the depression angle, then the underwater distance is the vertical side of the triangle.
If we denote Ф as the angle of depression ,d as the detection distance and x as the unknown depth of the submarine, using trigonometry:
x = d* sin Ф
thus
x= d * sin Ф = 238 feet * sin 23° = 92.994 feet ≈ 93 feet