Pls help me quick pls what is the answer

B

Step-by-step explanation:

this is the pythagorean theory because if you look you see that the rectangle has two right triangles inside

pythagorean theory is a^2 + b^2 = c^2

a is side length

b is side length

c is hypotenuse ( longest side)

answer: b

step-by-step explanation:

if you use photomath right away it will give you the answer not like this app that you have to wait for people.