4. Period with the digits 913 is called thousands period.
5. The digit in the ten thousand place is 1.
6. The value of 9 is hundred thousands.
Hope it will help you :)
Answer: 
Step-by-step explanation:
Since we have given that

And we know that θ is in the Fourth Quadrant.
So, Except cosθ and sec θ, all trigonometric ratios will be negative.
As we know the "Trigonometric Identity":

It must be negative due to its presence in Fourth quadrant.
Hence, 
X is greater than or equal to 67
1000/15 =66.6 =67