Area of Circle

Pi x r^2

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  • Created by: daanish
  • Created on: 25-05-10 15:05

Area of circle

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Pi x r^2

Example 1: The radius of a circle is 3 inches. What is the area? [IMAGE] (http://www.mathgoodies.com/lessons/vol2/images/area_example1.gif)

Solution:

A = Pi times r times r (http://www.mathgoodies.com/lessons/vol2/images/area_formula2.gif)

A (http://www.mathgoodies.com/lessons/vol2/images/A.gif) = 3.14 · (3 in) · (3 in)

A (http://www.mathgoodies.com/lessons/vol2/images/A.gif) = 3.14 · (9 in2)

A (http://www.mathgoodies.com/lessons/vol2/images/A.gif) = 28.26 in2

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Simultaneous Equation

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Solution

  • Equation 1: 2x + y = 7
  • Equation 2: 3x - y = 8

Add the two equations to eliminate the ys:

  • 2x + y = 7
  • 3x - y = 8
  • ------------
  • 5x = 15
  • x = 3
  • Now you can put x = 3 in either of the equations.
  • Substitute x = 3 into the equation 2x + y = 7:
  • 6 + y = 7
  • y = 1

So the answers are x = 3 and y = 1

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Comments

WhatsHisFace

:)

daanish

did you comment on my card?

WhatsHisFace

yeah why?

daanish

lol my first day on this site. i was suprised

SumayyahXD

Thanks, helped alot. x

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