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Lecture Comments (5)

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Post by Myat Kyu on October 19, 2015

Hi, for the second question (concentric circles), given the center of the circles, shouldn't the radius of the bigger circle be r1+r2? I don't understand how you got area of bigger circle = pi*r2^2, I believe the answer should be pi*(r2+r1)^2 - pi*r1^2.

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Post by Peter Ke on October 10, 2015

How did you get r2= 3? I don't see you solving that.

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Post by Enrique Salinas on June 21, 2014

i have one question on the first example about circles, were trying to find the area of circle two, but i cant figure out how you got 2/3r2+3/3r2=5/3r2=5 and then after your multiply it you said that r2=3 can you please explain to me how you got those answers?

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Last reply by: Professor Vilkus
Tue Jul 8, 2014 9:57 AM

Post by Enrique Salinas on June 19, 2014

i have one question on the first example about circles, were trying to find the area of circle two, but i cant figure out how you got 2/3r2+3/3r2=5/3r2=5 and then after your multiply it you said that r2=3 can you please explain to me how you got those answers?

Circles on the SAT

Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.

  • Intro 0:00
  • How Circles are Tested on the SAT 0:11
    • But Don't Bother with Any of This
    • How to Deal with Sections of a Circle
    • College Board Expects Mistakes Here
    • Circumference=Perimeter
  • Learn by Example: How Circle Problems Are Presented 5:18
    • Three Tangential Circles
  • Learn by Example: Concentric Circles 8:56
  • Learn by Example: Shaded Area with Combination Circles and Squares 11:53