how do is solve for B in pythagerium therum

Take c^2 minus a^2 and then find the sqaure root of whatever number you get

Normally A and B stand for the KNOWN sides in ythe theroum.

A^2 + B^2 = C^2 subtract A^2

B^2 = C^2 - A^2 take the square root

B = √ [ C^2 - A^2 ]