An easy way to draw a circle is to hold a string fixed at one end (for instance, with a pin) and attach a pen to the other end. Holding the string taut and drawing wherever the taut string allows gives a circle. This is the same technique you follow when using a compass. With a compass, the string is simply replaced by a metal or plastic structure, which usually has some markings to let you pick the radius of your circle. The radius of a circle is the only measure that you need to determine any other measure, such as the circumference or area. For instance, the circumference C of a circle (the length measured around the outside of the circle, i. e., the perimeter) is C=2πr. Suppose that you have a piece of string 7 cm long. If one end is held fixed and you draw with a pen at the other end, keeping the string tight, then you will draw a circle. Required:
a. What is the circumference of this circle?
b. Suppose that you needed to make a pen for some small animals. You have 12 m of fencing. You decide to make a circular pen, because if you wish to enclose an area using a given length of fencing, then a circular fence encloses a larger area than a fence of any other shape. What is the radius r of the pen?

The answer is "44 cm and 1.910 m".

Explanation:

In point a:

Formula for Circumference

In point b:

The formula for the radius of the pen:

most voltage drop calculators want the distance between the source and destination. then internally, they double it so both the source and return wires are calculated. but you need to know which distance the calculator uses so you're not half of what you should be or double what you should be.

most circuit breakers will not take a #6 directly, so the electrician will have to splice on a smaller pigtail. you also have to upsize the grounding wire when you upsized the ungrounded (hot) wire (see note in 250.122). this will preclude using most cable assemblies, as a cable with #6 copper will most likely only have a #10 grounding conductor. you need a #6 grounding conductor if the circuit is 20a. a #8 cable is no better, as it will have a #10 grounding conductor too. but most 20a breakers will take a #8 directly.

in your related post, you didn't say what type of load this is. if it is a light or heater, voltage drop won't be a big issue. if this is a motor, the current needs are huge at startup and the voltage drop can pose a problem. if this is a motor, knowing if the motor is under much load during startup will answer the voltage drop effect (a saw is easier to start than a compressor).

answer: the metamorphic rocks are formed when they are exposed to high pressure and high temperatures. this happens when one of the earth's plates comes in contact with the other plate by traveling in opposite directions, straight into each other or slipping under one another. the friction that is caused by this activity results in   melting of rocks and when it cools they are known as metamorphic rocks. this process needs a controlled amount of pressure and temperature otherwise it may turn into magma.