Last week, Wednesday's low temperature was 4.5°F, Thursday's low temperature was 1.2°F, Friday's low temperature was -2.7°F and Saturday's low temperature was 0.5°F. The average low temperature for the week was -1.5°F. How many of these days had low temperatures less than the average low temperature for the week?

You are standing next to a really big circular lake. you want to measure the diameter of the lake, but you don't want to have to swim across with a measuring tape! you decide to walk around the perimeter of the lake and measure its circumference, and find that it's 400\pi\text{ m}400? m. what is the diameter dd of the lake?