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
b
d. 145*2 is 290 than the total angle is 360 then minus 290 then divide by two