Marisa Wilkerson, 11th grader, and her classmate use their hands to make the shape of a conic section in Crystal Kirch's pre-calculus class at Segerstrom High School in Santa Ana, Calif., Wednesday, ... more 
Marisa Wilkerson, 11th grader, and her classmate use their hands to make the shape of a conic section in Crystal Kirch's pre-calculus class at Segerstrom High School in Santa Ana, Calif., Wednesday, Jan. 16, 2013. A growing number of teachers are implementing what is known as "flipped learning," in which students learn lessons as homework, mostly through online videos produced by teachers, and use classroom time to practice what they learned. (AP Photo/Jae C. Hong) less 
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Associated Press | Photo By Jae C. Hong
Sun, Jan 27, 2013 6:40 PM EST