I’m so sorry but i don’t understand this at all

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

Icould really use some with this question.

Which of the following are independent events? a) knowing that it is going to rain tomorrow, and bringing an umbrella to schoolb) knowing that you have to get up early tomorrow, and going to bed before 9 p.mc) knowing that it is going to rain tomorrow, and going to bed before 9 p.md) knowing that you have a test in school tomorrow, and studying thw night before