What is a tool used to create arcs and circles

Sanya noticed that the temperature was falling at a steady rate of 1.4 degrees every hour from the time that she first checked her outdoor thermometer. by 6 a.m., the temperature had fallen 21 degrees. which expression can you use to find how many hours earlier she had first checked the thermometer?

The volume of a cube-shaped shipping container is 13,824 cubic inches. find the edge length of the shipping container.

Find two numbers if their sum is 91 and the ratio is 6: 7?