70 m * (100cm)/(1m) * (1 in)/(2.54 cm) = 2755.9 in
.
Rough check, 1 m = 39.36 in approx , 70*39.36 = 2755.2
I think that's how it's done. As far as explaining it goes, I can't do that. I had to ask my math teacher and she wrote the calculations down.
