Permiter Of a Trapezoid

[Riot]

Can I please have a detailed explanation of how to solve this? I don't understand at all how to find the missing side and I can not find it online. I really need help, like for real? I need an explanation. Please and thank you.

 

[Novice]

Friend, you should be able to do this much on your own.
I have assumed that you know the Pythagoras theorem. Do you?

 

[Riot]

Im sorry

No. Im sorry I don't really know much...im doing on online geometry class and i'm having to teach myself pretty much....

 

[HallsofIvy]

Wow, you don't know the Pythagorean theorem? That's probably the most famous theorem in mathematics! If a right triangle has "legs" of length a and b (a leg is either of the two sides adjacent to the right angle) and "hypotenuse" of length c (the hypotenuse is the side opposite of the right angle), then \(\displaystyle c^2= a^2+ b^2\).