High school is four years of your life that you will NEVER get back, like ever. Four of the best years where you spent eight hours a day learning and being tested on things that you absolutely NEED to know when you graduate. Here are 15 things that I totally use every day outside of school.

1. Pythagorean Theorem

You seriously have no idea how many times I have to find the length of a hypotenuse of a right triangle after being given the lengths of sides A and B. It's actually quite ridiculous.

2. Periodic Table

If I didn't know that the periodic table was arranged "according to the number of protons that each element has in its atomic nucleus" I honestly don't know how I'd make it through the day.

3. Diagramming Sentences

Every time someone speaks to me I have this uncontrollable urge to write their sentence down and diagram it.

4. Truth Tables

To be completely honest, I have to figure out if two statements are "logically equivalent" all of the time. And I can't do it without truth tables!

5. Cursive

I write everything in cursive. If someone says I only write my signature in cursive, they're totally lying.

6. The number i

I can't even be sarcastic about this one....

7. Photosynthesis

LISTEN: If you don't remember anything else from high school, remember photosynthesis! You will need to know the feeding process of plants every single day of your life!

8. Logarithms

I spend 90% of my day finding the log of numbers. It's a hobby of mine.

9. How to dissect an animal

If you're a psychopath or a morgue worker, how to properly dissect animals is absolutely vital to know. I personally love knowing exactly how the inside of a pig, fish, and sheep heart looks like.

10. Different types of clouds

Every morning when I walk outside I study the clouds and decide what type of cloud it is. So far the most popular are cumulus.

11. How to find the mole

I find myself finding the mole all of the time actually. It's a very important skill.

12. Solving Matrices

The number of times I need a matrix to represent a linear transformation of a geometric object would blow your mind.

13. Finding congruent triangles

Every time I see a triangle I stop and find one that is perfectly congruent to it. It's almost like OCD. What would I do if I hadn't learned how to do that in high school?

14. How to analyze everything an author writes.

Seriously. How else would I know that when an author says "the curtain was blue" he really means that the curtain is a representation of his own sadness and depression which hides the light, I wouldn't.