Let k be the scale factor relating two similar prisms [tex] P_{1} [/tex] and [tex] P_{2} [/tex], such that for corresponding parts of prisms [tex] P_{1} [/tex] and [tex] P_{2} [/tex] (for heights, in particular) we have [tex]k= \frac{height\ of \ P_{1} }{height \ of\ P_{2} } [/tex]. In our case [tex]k= \frac{4}{10} = \frac{2}{5} [/tex].
For surfaces area we have [tex] \frac{Surface \ area \ of \ P_{1} }{Surface \ area \ of \ P_{2}} = k^{2} =( \frac{2}{5} )^{2}= \frac{4}{25} [/tex].
So, the right answer is 4:25 (choice B)
