Answer:
B.50
Explanation:
The two angles form a right angle ( indicated by the little square )
Right angles have a measure of 90 degrees
Hence, x + 10 + 30 = 90
( Note that we just created an equation that we can use to solve for x )
We now solve for x using the equation we created
x + 10 + 30 = 90
Combine like terms
x + 40 = 90
Subtract 40 from both sides
x = 50