Euler's formula, v − e + f = 2, relates the number of vertices v, the number of edges e, and the number of faces f, of a polyhedron. solve euler's formula for e.

V - E + F = 2add E to both sides
V + F = 2 + E ...now subtract 2 from both sides
V + F - 2 = E <==

The answer is 225 miles per 4.5 hours. hope this ; )

First step is to get rid of the square root. remember that a square root is the same as raising to the (1/2) power. see below: multiply exponents per exponent rules to get: remember you subtract exponents from the denominator and add exponents in the numerator so: simplify further: so a is the correct choice. if you don't understand this google exponent rules and it will you understand. look at the image results.