Find the arc length of the semicircle.

Step-by-step explanation:

The formula for arc length (at least the geometric formula) is

What we have here is a perfect semicircle.  A semicircle has a central angle measure of 180 degrees (that's our theta value) and this circle has a diameter of 12.  Therefore,

which simplifies nicely to

which simplifies even further to

which gives you an arc length of

AL = 18.84 units

first option

a function is a relation in which an input is paired with exactly one output.

so, let's find the right answer.

in our first option, our inputs are january, february, and march. the outputs are 30, 28, and 25. each input has it's own output. this is correct!

our second option we know is incorrect, because ms. valverade has two outputs, dogs and cats. this is not a function.

our third option is incorrect as well. the yellow square has two ouputs, the square and the triangle.

lastly, in our fourth option, we see the number 7 two times with a different output. therefore, this is not a function.

remember: each input must be paired with only one output!