Liana can see that the measure of Angle L and Angle M form a straight line. Since Liana knows that a straight line has an angle measure of 180 degrees, what is the measure (in degrees) of Angle M?

150 degrees

Step-by-step explanation:

Let's start off by looking at what we are working with in this specific problem:

We can see that we are looking at 2 angles, angle L and angle M, that add up to a total of 180 degrees (aka a straight line)

Now that we know that, we also have to keep is mind that angle L + angle M = 180 degrees.

Now that we've got all of that out of the way, let's set up a simple algebraic equation:

angle L + angle M = 180

We also know that angle L is 30 degrees so let's add it into the equation we have just created:

30 + angle M = 180

We now know that 30 plus angle M (whatever it might be) is equal to 180 so in order to solve this problem we have to do some simple subtraction.

180 - 30 = angle M

Now we are left with:

150 degrees = angle M