Question

HELP HELPP PLEASEEEE!

Answer 1

Explanation:

volume of pyramid with square base=a^2(h/3)

84=a^2*7/3

84*3/7=a^2

252/7=a^2

36=a^2

`\sqrt{36`=a

6=a

therefore length=6

Answer 2

the length is b 12 !