Difference between revisions of "2016 AMC 12B Problems/Problem 6"

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==Solution==
 
==Solution==
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Plotting points B and C on the graph shows that they are at (-x,x^2) and (x,x^2), which is isosceles. By setting up the triangle angle formula you get: 64=1/2*2x*x^2 =  64=x^3 Making x 4, and the length of BC is 2x, so the answer is 8.
  
 
==See Also==
 
==See Also==
 
{{AMC12 box|year=2016|ab=B|num-b=5|num-a=7}}
 
{{AMC12 box|year=2016|ab=B|num-b=5|num-a=7}}
 
{{MAA Notice}}
 
{{MAA Notice}}

Revision as of 12:34, 21 February 2016

Problem

All three vertices of $\bigtriangleup ABC$ lie on the parabola defined by $y=x^2$, with $A$ at the origin and $\overline{BC}$ parallel to the $x$-axis. The area of the triangle is $64$. What is the length of $BC$?

$\textbf{(A)}\ 4\qquad\textbf{(B)}\ 6\qquad\textbf{(C)}\ 8\qquad\textbf{(D)}\ 10\qquad\textbf{(E)}\ 16$

Solution

Plotting points B and C on the graph shows that they are at (-x,x^2) and (x,x^2), which is isosceles. By setting up the triangle angle formula you get: 64=1/2*2x*x^2 = 64=x^3 Making x 4, and the length of BC is 2x, so the answer is 8.

See Also

2016 AMC 12B (ProblemsAnswer KeyResources)
Preceded by
Problem 5
Followed by
Problem 7
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
All AMC 12 Problems and Solutions

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