Given any 1 known variable of a circle, calculate the other 3 unknowns. Pareidolia: Why Do We Think There’s A Giant Rabbit On The Moon? So, the radius of a circle with an area of 21 square centimeters is about 2.59 centimeters.Areas always use square units (like square centimeters), but the radius always uses units of length (like centimeters). For any regular polygon, the radius is the same from the center to all its vertices. Can We Make The Fictional Metal Used In Captain America’s Shield (Vibranium)? X 5 Productivity hacks you NEED for working from home. If the diameter of a circle is 8.8cm, then the radius turns out to be 4.4cm. This article has been viewed 2,881,787 times. we respect your privacy and take protecting it seriously, The word radius traces its origin to the Latin word, Gravitational Lensing: What It Is And How It Is Helping Us Discover New Galaxies, What Exactly is Archimedes Principle: Explained in Simple Words, What is Evolution? But in practice, the lens will have terrible distortion, and shift in focal length, as well as vignetting, beyond its rated image circle size. The formula is C=2πr{\displaystyle C=2\pi r} , where C{\displaystyle C} equals the circle’s circumference, and r{\displaystyle r} equals its radius. ; Circle centered at any point (h, k),(x – h) 2 + (y – k) 2 = r 2where (h, k) is the center of the circle and r is its radius. How Do You Find the Area of a Circle if You Know the Radius? Task 1: Given the radius of a cricle, find its area. See How the arc radius formula is derived. Finding Centre and Radius of Circle From Complex Numbers - Examples. This article was co-authored by our trained team of editors and researchers who validated it for accuracy and comprehensiveness. = pi (5.5 * 5.5 ) If you know the radius of a circle, you can use it to find the area of that circle. Area of a Circle Calculator. To find the length of chord, we may use the following theorem. Enter the radius, diameter, circumference or area of a Circle to find the other three. The diameter is two times the radius, so the equation for the … The area of a circle calculator helps you compute the surface of a circle given a diameter or radius.Our tool works both ways - no matter if you're looking for an area to radius calculator or a radius to the area one, you've found the right place . And to find the volume of the hollow sphere we apply the formula,  4/3π R3-4/3π r3. That gives you the circumference of the circle. Problem: Find the circumference of a circle that has an area of 78.5 m. squared. Here we are going to see how to find radius of circle when length of chord is given. Include your email address to get a message when this question is answered. So, now if you know the width of the circle, otherwise called the diameter, you can simply divide it by 2 to get the radius. Ingestion To Excretion: Journey of Food from the Time it Enters our Body to the Time it Leaves. Either will do — they’re the same length. Other terms associated with circle are sector and chord. How do I calculate the area of a circle using the radius? We know ads can be annoying, but they’re what allow us to make all of wikiHow available for free. Not technically a "calculation.". It’s a common question for all of us, especially all school-going children. Enter radius of circle 7 Area of circle : 153.909 In above program, we first take radius of circle as input from user and store it in variable radius. You can find the radius of a circle very quickly by dividing the value of any circumference by 6.28. The circumference is equal to the radius multiplied by 2pi. The straight line from the center to one slice of the pizza is the radius. The video provides two example problems for finding the radius of a circle given the arc length. The calculations are done "live": How to Calculate the Area. Dimensions of … If you know the radius of a circle, you can use it to find the area of that circle. How to Calculate the Radius From the Circumference Understanding Circumference. The diameter is a special type of chord, a line that joins any two points of a circle. She is a voracious reader and a creative writer. Just plug that value into the formula for the area of a circle and solve. Technically you can't "calculate" the radius in such a situation. The circumference of a circle is the distance around a circle's edge. Calculate the area, circumference, radius and diameter of circles. A Simple and Brief Explanation, What is the Heisenberg Uncertainty Principle: Explained in Simple Words. All tip submissions are carefully reviewed before being published, This article was co-authored by our trained team of editors and researchers who validated it for accuracy and comprehensiveness. Here are the circle equations: Circle centered at the origin, (0, 0), x 2 + y 2 = r 2 where r is the circle’s radius. Radius of a circle is the distance from the center to the circumference of a circle. If you want to know how to calculate the diameter of a circle, just follow these steps. The area of a circle is equal to pi times the radius squared. Perpendicular from the centre of a circle to a chord bisects the chord. If you keep track of units in this problem, you'll notice that cm2=cm{\displaystyle {\sqrt {cm^{2}}}=cm}. The diameter is the distance from one side of the circle to the other at its widest points. Substitute this value to the formula for circumference: C = 2 * π * R = 2 * π * 14 = 87.9646 cm. % of people told us that this article helped them. This means that the sector is 13{\displaystyle {\frac {1}{3}}} of the circle.Your equation should now look like this: 50=13(π)(r2){\displaystyle 50={\frac {1}{3}}(\pi )(r^{2})}, Example50=13(π)(r2){\displaystyle 50={\frac {1}{3}}(\pi )(r^{2})}5013=13(π)(r2)13{\displaystyle {\frac {50}{\frac {1}{3}}}={\frac {{\frac {1}{3}}(\pi )(r^{2})}{\frac {1}{3}}}}150=(π)(r2){\displaystyle 150=(\pi )(r^{2})}, Example150=(π)(r2){\displaystyle 150=(\pi )(r^{2})}150π=(π)(r2)π{\displaystyle {\frac {150}{\pi }}={\frac {(\pi )(r^{2})}{\pi }}}47.7=r2{\displaystyle 47.7=r^{2}}. Hold the zero mark of the ruler steady against the circle, and slowly move the other end back and forth around the circle's edge. Divide the circumference by using the centre and radius of a circle sector, not the area a. Be calculated.For example: enter the radius of a circle is a section the. The formula, 4/3π R3-4/3π r3 the easiest way to measure the size of the of! Do you calculate the area of a circle to find the other 3.... 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