Acute and obtuse angles.
OK, these are important words to learn...watch the powerpoint again if you need to!
I always remember that acute angles are cute (smaller than a right angle)
I always felt that obtuse sounded like a big word! (bigger than a right angle)
A right angle measures 90 degrees....and a protractor is used to measure angles - you may have seen them, they look like half circles with numbers on.
You will learn to do that in year 4/5 all you need to remember now is that a right angle = 90 degrees.