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You didn't think Ellipses would be on AMC 10 ...

Source: 2019 AMC 10B #10/2019 AMC 12B #6

February 14, 2019
conicsellipseAMC 10AMCAMC 10 BAMC 12AMC 12 B

Problem Statement

In a given plane, points AA and BB are 1010 units apart. How many points CC are there in the plane such that the perimeter of ABC\triangle ABC is 5050 units and the area of ABC\triangle ABC is 100100 square units?
<spanclass=latexbold>(A)</span>0<spanclass=latexbold>(B)</span>2<spanclass=latexbold>(C)</span>4<spanclass=latexbold>(D)</span>8<spanclass=latexbold>(E)</span>infinitely many<span class='latex-bold'>(A) </span>0\qquad<span class='latex-bold'>(B) </span>2\qquad<span class='latex-bold'>(C) </span>4\qquad<span class='latex-bold'>(D) </span>8\qquad<span class='latex-bold'>(E) </span>\text{infinitely many}