How to find the Perimeter or Circumference of a Circle : A great mnemonic for kids HD

Weekly, viral Math puzzles, problems and tricks with answers and explanations for kids and adults alike For my full course on Speed Math Techniques please go here : http://rshankar.com/courses/vedic Click on link to watch all our videos : https://www.youtube.com/playlist?list=PL1-lK8m-elLDitldLRadlsvuCFQVbkgVI Script: Hi Guys and welcome to another Math Tip and Tricks video. How to find the Perimeter or Circumference of a Circle : A great mnemonic for kids In this video I am going to talk about Circles. And to be more specific, we will look at how to calculate the perimeter OR circumference of a Circle. But lets start with some concepts. So let me first draw a circle. this point here is the center of the circle. Now lets draw a line from the center of the circle to a point on the circle like this. This my friends is the radius of the circle. Lets assume we measured this radius and it was 5 cm. So we can say that the circles radius is 5 cm. Now just to be very clear, I can draw lines like this from the center to any other point on the circle and each of these lines would also be called the radius and each of them would be 5 cm in length Now what if I drew a straight line like this starting at one point on the circle, passing through the center and going all the way to another point in the circle. Some of you may say that this is one radius here and this is another one here. You are right. But there is another term for such a line. its called the diameter of the circle. Pause the video now and make sure you understand the difference between the radius and the diameter . Let me right this down: Diameter = Radius times 2 Now let us look at another concept. The circumference of a circle. First let us see what it represents. The circumference of a circle represents the distance around it. So imagine you start walking along the boundary of this circle . if you did one round , you will cover a distance equal to the circumference of the circle. Lets now see the formula to calculate the circumference Here it is Circumference = Pie X Diameter OR C = PIE x D So here is our first problem. A circle has a diameter of 10 cm. What is its circumference? Ok, time for our shiny formula C = Pie x D Lets replace this pie symbol with its actual value. We get C = 3.14 X D And lets replace D with its value which is 10. So we get C = 3.14 x 10 which gives us 31.42 cm Lets look at one more question A circle has a radius of 7 cm. What is its circumference? Lets go back to our formula C = Pie x D Oye, there is no radius here. What to do? No worries, lets just get one. We saw earlier that the diameter is twice the radius. So lets use this knowledge to change our formula. So our formula could be written as Pie x 2 x r And lets use this formula So the circumference of a circle with radius 7 is 2 x 3.14 x 7 and this gives us xxxxx Now having a formula is great. But its important to remember it right. So here is a little tip to remember our formula Lets wr