On a scale drawing, 1 millimeter equals 4 centimeters. if a line on the drawing is 45 millimeters, how many meters is it actually?

A20? -foot ladder is placed against a vertical wall of a? building, with the bottom of the ladder standing on level ground 19 feet from the base of the building. how high up the wall does the ladder? reach?

I'm at a bookstore with $\$35$ in my pocket and a $20\%$-off coupon. what is the cost of the most expensive book i can buy with my money and the coupon? (assume that there are books of every possible price in the bookstore. it's a large bookstore! )

Alex measured the length of an item to be 3.7 cm. the actual length is 3.5 cm. what is alex’s percent error?