The answer is c. 0.7 is in every set of pairs so you would get the same product by multiplying all of them the way c has it.
He is incorrect because if the ratio is that for every 6 ft on the model is 8 feet in real life, he already exceeded his Kennedy's height by 2.
I'm guessing you are asking what a number raised to the third power would be called, in that case it'd be called cubed :)
Answer: the numbers can be 16 and 9, 6 and 24 or other factors of 144