A 10-foot board rests against the wall. The angle that the board makes with the ground is 60 degrees. How far is the base of the board away from the wall?

Select the correct trig ratio and distance from the wall.

1 answer

To find the distance from the base of the board to the wall, we can use the cosine function from trigonometry. The cosine of an angle in a right triangle is defined as the adjacent side divided by the hypotenuse.

In this scenario:

  • The hypotenuse is the length of the board, which is 10 feet.
  • The angle with the ground is 60 degrees.
  • The side adjacent to the angle (the distance from the wall) can be found using the cosine function.

Using the cosine function:

\[ \cos(\theta) = \frac{\text{adjacent}}{\text{hypotenuse}} \]

Here, \(\theta = 60^\circ\), and we can denote the distance from the wall as \(d\). Thus:

\[ \cos(60^\circ) = \frac{d}{10} \]

We know that:

\(\cos(60^\circ) = \frac{1}{2}\)

Now we can substitute this value into the equation:

\[ \frac{1}{2} = \frac{d}{10} \]

Next, solve for \(d\):

\[ d = 10 \cdot \frac{1}{2} = 5 \text{ feet} \]

Therefore, the distance from the base of the board to the wall is 5 feet.