Answer:
a. sine
Step-by-step explanation:
As it can be seen from the figure, triangle ABC is the right-angled triangle with Angle C is equal to 90 degree.
In a right-angled triangle, there is a formula as following:
<em>+) sine (an acute angle) = (length of its opposite side)/ hypotenuse</em>
In the figure, angle B and length of the hypotenuse are given.
As x is the length of AC and AC is the opposite side to angle B
=> So that we can use sine to find x
