Answer :
Setup a right triangle with the boat on top. Striaght down is 40 feet. The rope makes the hypotenuse at 140 feet. The floor of the ocean makes the third side.
40^2 + x^2 = 140^2
When you solve for "x" you get 134.2 feet.
Hope that helps.
the triangle is actually 40 down, x across, and 95 for the hypotenuse. 40²+x²=95². you can try the rest of it first and ask if you need help. ok 86.2feet