Given the following right triangle, what is the measure of angle b

need the arctan of the 2 lengths given

9/12 reduces to 3/4

arctan on the calculator is tan^-1

 arctan(3/4) = 36.86989 degrees

 round off the answer as needed

the entire expression should be subtracted from 30. to subtract the quantity, distribute the negative sign, which changes the signs on the terms. so, the –2 changes to positive and gets added to 30 instead of subtracted from it.

hope this ! ^w^

your answer would be 12