Difference between revisions of "2011 AMC 10A Problems/Problem 9"

(Created page with 'A rectangular region is bounded by the graphs of the equations y=a, y=-b, x=-c, and x=d, where a,b,c, and d are all positive numbers. Which of the following represents the area o…')
 
 
(9 intermediate revisions by 6 users not shown)
Line 1: Line 1:
A rectangular region is bounded by the graphs of the equations y=a, y=-b, x=-c, and x=d, where a,b,c, and d are all positive numbers. Which of the following represents the area of this region?
+
== Problem 9 ==
  
We have a rectangle of side lengths <math>(a - -b)</math> and <math>(d - -c)</math> Thus the area of this rectangle is <math>(a + b)(c + d) = ac + ad + bc + bd</math>
+
A rectangular region is bounded by the graphs of the equations <math>y=a, y=-b, x=-c,</math> and <math>x=d</math>, where <math>a,b,c,</math> and <math>d</math> are all positive numbers. Which of the following represents the area of this region?
 +
 
 +
<math> \textbf{(A)}\ ac+ad+bc+bd\qquad\textbf{(B)}\ ac-ad+bc-bd\qquad\textbf{(C)}\ ac+ad-bc-bd  \quad\quad\qquad\textbf{(D)}\ -ac-ad+bc+bd\qquad\textbf{(E)}\ ac-ad-bc+bd </math>
 +
[[Category: Introductory Geometry Problems]]
 +
 
 +
== Solution ==
 +
 
 +
We have a rectangle of side lengths <math>a-(-b)=a+b</math> and <math>d-(-c)=c+d.</math> Thus the area of this rectangle is <math>(a + b)(c + d) = \boxed{\textbf{(A)}\ ac + ad + bc + bd}</math>.
 +
 
 +
==Video Solution==
 +
https://youtu.be/n0qUd4ukEF8
 +
 
 +
~savannahsolver
 +
 
 +
== See Also ==
 +
 
 +
{{AMC10 box|year=2011|ab=A|num-b=8|num-a=10}}
 +
{{MAA Notice}}

Latest revision as of 18:56, 17 November 2020

Problem 9

A rectangular region is bounded by the graphs of the equations $y=a, y=-b, x=-c,$ and $x=d$, where $a,b,c,$ and $d$ are all positive numbers. Which of the following represents the area of this region?

$\textbf{(A)}\ ac+ad+bc+bd\qquad\textbf{(B)}\ ac-ad+bc-bd\qquad\textbf{(C)}\ ac+ad-bc-bd   \quad\quad\qquad\textbf{(D)}\ -ac-ad+bc+bd\qquad\textbf{(E)}\ ac-ad-bc+bd$

Solution

We have a rectangle of side lengths $a-(-b)=a+b$ and $d-(-c)=c+d.$ Thus the area of this rectangle is $(a + b)(c + d) = \boxed{\textbf{(A)}\ ac + ad + bc + bd}$.

Video Solution

https://youtu.be/n0qUd4ukEF8

~savannahsolver

See Also

2011 AMC 10A (ProblemsAnswer KeyResources)
Preceded by
Problem 8
Followed by
Problem 10
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 10 Problems and Solutions

The problems on this page are copyrighted by the Mathematical Association of America's American Mathematics Competitions. AMC logo.png