The formula for converting from Celsius to Fahrenheit is F=9/5C+32. The Fahrenheit temperature of a certain city has never dropped below 77° How would you describe this using Celsius temperature? It has never dropped below ___ °C.

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?