Today we are going to look at angles. The first angle we are going to look at is the ninety degree angle. That makes an L shape and the symbol is a little square box in the corner. Then we have what is called a straight angle which is straight across without an actual angle. I think of it as just a straight line. Then you have an angle that falls smaller than ninety degrees. That one is an acute angle, and then you have an angle that is larger than ninety, but less than straight and that is an obtuse angle so let’s label those. This first one is ninety, and that is kind of your reference and you always want to be familiar with a ninety degree in order to see if an angle is smaller than it. That one would be an acute angle because it is less than ninety and this one is larger than ninety and you can sketch in your L if you want to in order to compare it, and that one is greater so it is obtuse and then a straight line is one hundred and eighty because it is kind of like two L‘s put together and ninety and ninety is one eighty so this is your straight angle. So you are always comparing to your ninety degree angle or your right angle. So that’s how angles classify. So let’s look at the rules. An acute angle is less than ninety degrees. A right angle is equal to ninety degrees and it is your reference angle. An obtuse angle is greater than ninety degrees and a straight angle which is equal to one hundred and eighty degrees. You can also use a protractor to measure an angle and when you use a protractor take the dot and line it up with the vertex. What is the vertex? It is the corner of the angle. Line it up, read it from the bottom up. This is how you classify angles.