Use the given information to prove that <4~=<3 the prove is <4=~<3 just and don't know what the reason is ?

The square pyramid has a volume of 441 cubic inches. what is the value of x? 1/7x is the height x is the base

1- what do you think the product of a nonzero rational number and an irrational number is? is it rational or irrational? make use of variables, the closure property of integers, and possibly a proof by contradiction to prove your hypothesis.2- why do we have to specify that the rational number must be nonzero when we determine what the product of a nonzero rational number and an irrational number is? if the rational number were 0, would it give us the same result we found in the first question?

Can someone me with #s 8, 9, and 11. with just one of the three also works. prove using only trig identities.