Question

A 15 foot board rests against a 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?

Answer 1

Let the base of the board is x feet away from the wall .

And the hypotenuse, which is represented by the length of the board be 15 foot .

So here we have adjacent represented by the base and the hypotenuse .

And cosine function relates adjacent and hypotenuse , which is

`cos 60 = (15)/(x)`

And the value of cos 60 is half .

`(1)/(2)= (x)/(15)`

Performing cross multiplication

`2x=15`

Dividing both sides by 2

`x=7.5 ft`

Correct option is A .