I suck at this type of math because the teacher did not explain good enough and I’m stuck.

21

Step-by-step explanation:

2^2+b^2=5^2

4+b^2=25

b^2=21

11.2

step-by-step explanation:

when doing tangent the tangent of the angle is equal to the opposite side from the angle over the adjacent side to the angle.

tan43 = x / 12

move 12 over by multiplying each side by 12

12tan43 = x

x = about 11.2