Someone help me please im bad at this =(

Geometry answer picture question pls . reason and statements

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?

Aright triangle has an area of 21 m2. the dimensions of the triangle are increased by a scale factor of 4. what is the area of the new triangle