Five times a number less than one hundred.
Answer: 
<u>Step-by-step explanation:</u>
Given: cos x =
, x is in Quadrant 4
Use Pythagorean Theorem to find sin x:
8² + y² = 17²
y² = 17² - 8²
y² = 289 - 64
y² = 225
y = 15
→ sin x = 
Use the double angle formula to find cos (2x):

Answer:
X = 9
okay If I'm wrong sry what's 9x3 it's 45 right ( me not using a caluctalter ) ( I didn't even spell that Right lol ) but anyways it's X=9
The irrational in between should be 7.8
The square root of 81 is 9