How do you find x based off the midsegment triangle?

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?

Arectangular garden is 5 feet long and 3 feet wide. a second rectangular garden has dimensions that are double the dimensions of the first garden. what is the percent of change in perimeter from the first garden to the second garden?

Which angle of rotation is an angle of rotational symmetry for all figures?