The correct answer is:
B) The width of a wide river .
Step-by-step explanation:
We can use trigonometric ratios to find the distance across a river, so long as we know the base of the triangle formed and one of the angles. For example:
"A farmer needs to find the width of a river that flows through his pasture. He places a stake (Stake 1) on one side of the river across from a tree stump. He then places a second stake 50 yards to the right of the first (Stake 2). The angle formed by the line from Stake 1 to Stake 2 and the line from Stake 2 to the tree stump is 72º. Find the width of the river to the nearest yard. "
After we draw the diagram, we see that we have the side adjacent to the 72° angle and are looking for the side opposite this angle. Opposite/adjacent is the ratio for tangent; we get the equation
tan 72 = x/50
Multiply both sides by 50:
50 tan 72 = (x/50)* 50
50 tan 72 = x
153.88 = x
154 ≈ x