I need help doing this question it is 7th grade math

1. the wheeling bridge in west virginia is about 307 meters long. if you walk with a stride of about meter, about how many steps would it take you to cross this suspension bridge?

In triangle △abc, ∠abc=90°, bh is an altitude. find the missing lengths. ah=4 and hc=1, find bh.

The volume of gas a balloon can hold varies directly as the cube of its radius. imagine a balloon with a radius of 3 inches can hold 81 cubic inches of gas. how many cubic inches of gas must be released to reduce the radius down to 2 inches?