I don’t understand how to this this will someone help?

If kn = 9 cm, mn = 21 cm, rs = 42 cm, and ps = 18 cm, what is the scale factor of figure klmn to figure pqrs?

5× 1/2 = ? a) more than 5 because you are multiplying by a whole number b) 5/10 because you multiply the numerator and denominator by 5 c) less than 5 because you are multiplying by a number that is more than 1 d) less than 5 because you are multiplying by a number that is less than 1

The deepest part of the swimming pool is 12 feet deep.the shallowest part of the pool is 3 feet deep.what is the ratio of the deeply of the deepest part of the pool to depth of the shallowest part of a pool?