Is their a picture for the problem
First magnitude...
d^2=5^2+3^2
d^2=25+9
d^2=34
d=√34
now for direction...
tanα=y/x
α=arctan(y/x) and we know y=5 and x=3 so
α=arctan(5/3)
α≈59.03624
So the vector of her ride is:
√34, 59.03624° or if you prefer...
√34, 59°2'10" (in standard angle position)
2^2 x 5 x 7 =140
^ is used to represent exponent
8km=5miles
1miles= 5/8=0.625mile
100km = 100x0.625=63.5 miles