45 centimeters is equal to how many inches

Guests at an amusement park must be at least 54 inches tall to be able to ride the roller coaster. which graph represents the set of heights that satisfy this requirement?

How to do this , and can some one explain

According to the 2008 u.s. census, california had a population of approximately 4 × 10^7 people and florida had a population of approximately 2 × 10^7 people. which of the following is true? a. the population of florida was approximately two times the population of california. b. the population of florida was approximately twenty times the population of california. c. the population of california was approximately twenty times the population of florida. d. the population of california was approximately two times the population of florida.