Question

I need some help please

Answer 1

The definition of the tangent function tells you
   tan(angle) = (300 ft) / (distance to mountain)
This equation can be rearranged to
   (distance to mountain) = (300 ft) / tan(angle)

For the far end of the river,
   distance to far end = (300 ft) / tan(24°) ≈ 673.8 ft

For the near end of the river
   distance to near end = (300 ft) / tan(40°) ≈ 357.5 ft

Then the width of the river can be calculated by finding the difference of these distances:
   width of river = distance to far end - distance to near end
   width of river = 673.8 ft - 357.5 ft
   width of river = 316.3 ft

The appropriate answer choice is
   316 ft.