Question 623063
Since the side you have is the adjacent side and the side you want is the hypotenuse, cos is the correct function to use. Apparently something wen wrong in how you used cos.<br>
Think about this: The hypotenuse is <i>always</i> the longest side of a right triangle. So how could it be 9.7 when the adjacent side is 11? It can't. It has be longer than 11. We already know that the only possible answers are (a) or (c).<br>
cos is adjacent over hypotenuse. So the equation you should start with is:
{{{cos(28) = 11/x}}}
(I suspect that you had the ratio upside down.) To solve this we get rid of the fraction by multiplying each side by x:
{{{x*cos(28) = 11}}}
Then we solve for x by dividing both sides by cos(28):
{{{x = 11/cos(28)}}}<br>
Now we reach for our calculator:
{{{x = 11/0.88294759}}}
{{{x = 12.45827056}}}