I understand that it means that out of every 10 hours, a cat spends 7 sleeping (not 7 hours in a day).
this means that a cat is sleeping

a percentage stays constant, this means that a cat sleeps 70 % of each 10 hours, but also 70% of the day.
Use the Pythagorean theorem
let = length of ram = l
l² = 4² 18²
l² = 16 + 324
l² = 340
l = 18.4390889146
l = 18.4 ft.
To determine the position of a point