One side of a regular octagon is 4 inches long. what is the length of another side of the octagon?

32 inches
8 inches
4 inches
can't be determined

A regular octagaon has 8 equal sides 

so it only makes sense to say that the other side of an octagon would be 4 inches too!

But  if you want to know the total length,  multiply 8 x 4 = 32 inches!  
BUT THIS IS ONLY IF ITS A REGULAR OCTAGON 

otherwise it can't be really determined since I don't know its symmetry or the angles!!

Hope I answered your question! :)

70(5) + 175(8) + 35(4) =
350 + 1400 + 140 = 1890