Somebody plz help

You are living in aldine, tx and you are planning a trip to six flags in arlington, tx. you look on a map that has a scale of 0.5 inches to 30 miles. if the map shows the scale distance from aldine to arlington is 4 inches, how far is the actual distance?

How many four digit even numbers can be formed from digits 1,2,3,4,5 if repetition is allowed. how can solve this using permutation formula

The formula for the area of a regular polygon is a=1/2ap . what is the equation solved for a?