Note, if you have a linear scale, then the surface will be the square of this scale & the volume will be the cube of the linear
1) spheres. Yes they are similar. The linear scale factor is 8/5 & the ratio of the corresponding volumes is 8³/5³ =512/125
2) They are not similar since te ratio of te corresponding sides have different ratio
3) The linear scale is 1/2 so the ratio of their respective are will be 1/2² (=1/4) & the volume ratio will be 1/2³ (=1/8)
So the area of the second similar figure = 208x1/4 =52 in²
and the volume = 24 in³
4) Linear scale =3/4. Square Ration =9/16 (3²/4²) & Volume Ratio =27/64 (3³/4³)
So the area of the second similar figure = (9/16π) x96=54π in²
and the volume = (27/64π) x96 = 40.5π in³