Step-by-step explanation:

You could either:
a) Use the Pythagorean Theorem
b) Use Sine/Cosine/Tangent Inverse to find one of the angles, and then use that angle to find x.
5.4
That's your answer because if the number is 5 or larger, you round up. Because 6 is larger than 5, it rounds up to zero and then the 3 becomes a 4.