An angle of 1 radian is the angle subtended by an arc with the same length as the radius shown below.

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__Conversions between radians and degrees__

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__Arc Length__

The formula to find the arc length is illustrated below:Here, r is the radius and θ is the angle in radians.

If you had to find the arc length of a sector with a radius of 5cm and an angle of 80°, you would answer the question using this method - shown below.

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__Area of a Sector__

The area of a sector can be found using this formula.

If we had to find the area of the sector in the previous example, we would use a method like this.

I remember in high school thinking that I'll never get to use these formulas ever again. Boy was I wrong. I use the circle formula way too often when I'm helping program games with my friends. Good thing that my high school teacher was persistent with me until I learned it.

ReplyDeletemy blog: http://sulfen.com

It is nice to know that maths still serves you to this day.

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