Answer:
C (86.113)
Explanation:
First, find the missing angle B. Since angles in a triangle add upp to 180,
180-26-90= 64
Then use the formula a/sina = b/sinb
' a' in the formula is the missing length X and sina is the corresponding(opposite) angle of X which is sin64.
B in the formula would be 42 and sinb is sin26 (the angle).
Substitute all values into the formula,
X/sin64 = 42/ sin26
Shift sin64 to the right side:
X= 42(sin64)/ sin26
X= 86.113
Hope this makes sense:)