memorization schmemorization

one thing that really bothers me about school is when teachers expect you to remember formulas and other schematics for solving problems.  don't they know that right after a test, test takers usually forget about 70% of the information they learned for the test? and if that formula isn't part of that 70% of information that we forget, why do we need to memorize it in the first place? when are we ever going to be in a situation where we need the formula or whatever it may be and not be able to look it up? i realize that this doesn't apply to concepts in the least bit. i'm not saying that we should never have to learn material and retain it in our memory because that would be a completely outrageous idea to say or believe.  conceptual material is a completely different case because, not only do you need to know it, but you need to be able to understand it on a deep level and then apply it to situations which can only be accomplished through some level of understanding.  formulas, like the formula used to calculate the volume of a trapezoid, volume = ½(A+B)*Y*Z, are always going to be accesible, rather quickly might i add with the help of the internet.  we shouldn't have to waste our time trying to cram our brains chalk full of the equations when they are so readily accessible.  i really wish more teachers and professors would catch on to this and realize it is completely unnecessary.  i know i praise the teachers that already believe in this.