Found problems: 663
2008 Balkan MO Shortlist, G3
We draw two lines $(\ell_1) , (\ell_2)$ through the orthocenter $H$ of the triangle $ABC$ such that each one is dividing the triangle into two figures of equal area and equal perimeters. Find the angles of the triangle.
2013 AMC 12/AHSME, 11
Triangle $ABC$ is equilateral with $AB=1$. Points $E$ and $G$ are on $\overline{AC}$ and points $D$ and $F$ are on $\overline{AB}$ such that both $\overline{DE}$ and $\overline{FG}$ are parallel to $\overline{BC}$. Furthermore, triangle $ADE$ and trapezoids $DFGE$ and $FBCG$ all have the same perimeter. What is $DE+FG$?
[asy]
size(180);
pen dps = linewidth(0.7) + fontsize(10); defaultpen(dps);
real s=1/2,m=5/6,l=1;
pair A=origin,B=(l,0),C=rotate(60)*l,D=(s,0),E=rotate(60)*s,F=m,G=rotate(60)*m;
draw(A--B--C--cycle^^D--E^^F--G);
dot(A^^B^^C^^D^^E^^F^^G);
label("$A$",A,SW);
label("$B$",B,SE);
label("$C$",C,N);
label("$D$",D,S);
label("$E$",E,NW);
label("$F$",F,S);
label("$G$",G,NW);
[/asy]
$\textbf{(A) }1\qquad
\textbf{(B) }\dfrac{3}{2}\qquad
\textbf{(C) }\dfrac{21}{13}\qquad
\textbf{(D) }\dfrac{13}{8}\qquad
\textbf{(E) }\dfrac{5}{3}\qquad$
1969 IMO Longlists, 9
$(BUL 3)$ One hundred convex polygons are placed on a square with edge of length $38 cm.$ The area of each of the polygons is smaller than $\pi cm^2,$ and the perimeter of each of the polygons is smaller than $2\pi cm.$ Prove that there exists a disk with radius $1$ in the square that does not intersect any of the polygons.
1997 India National Olympiad, 4
In a unit square one hundred segments are drawn from the centre to the sides dividing the square into one hundred parts (triangles and possibly quadruilaterals). If all parts have equal perimetr $p$, show that $\dfrac{14}{10} < p < \dfrac{15}{10}$.
2008 HMNT, 5
Joe has a triangle with area $\sqrt{3}.$ What's the smallest perimeter it could have?
2005 Sharygin Geometry Olympiad, 2
Cut a cross made up of five identical squares into three polygons, equal in area and perimeter.
2013 NIMO Problems, 8
Let $AXYZB$ be a convex pentagon inscribed in a semicircle with diameter $AB$. Suppose that $AZ-AX=6$, $BX-BZ=9$, $AY=12$, and $BY=5$. Find the greatest integer not exceeding the perimeter of quadrilateral $OXYZ$, where $O$ is the midpoint of $AB$.
[i]Proposed by Evan Chen[/i]
2011 Purple Comet Problems, 2
The diagram below shows a $12$-sided figure made up of three congruent squares. The figure has total perimeter $60$. Find its area.
[asy]
size(150);
defaultpen(linewidth(0.8));
path square=unitsquare;
draw(rotate(360-135)*square^^rotate(345)*square^^rotate(105)*square);
[/asy]
2015 AMC 10, 20
A rectangle has area $A \text{ cm}^2$ and perimeter $P \text{ cm}$, where $A$ and $P$ are positive integers. Which of the following numbers cannot equal $A+P$?
$ \textbf{(A) }100\qquad\textbf{(B) }102\qquad\textbf{(C) }104\qquad\textbf{(D) }106\qquad\textbf{(E) }108 $
2014 India PRMO, 4
In a triangle with integer side lengths, one side is three times as long as a second side, and the length of the third side is $17$. What is the greatest possible perimeter of the triangle?
2011 AMC 10, 14
A rectangular parking lot has a diagonal of $25$ meters and an area of $168$ square meters. In meters, what is the perimeter of the parking lot?
$ \textbf{(A)}\ 52 \qquad
\textbf{(B)}\ 58 \qquad
\textbf{(C)}\ 62 \qquad
\textbf{(D)}\ 68 \qquad
\textbf{(E)}\ 70 $
2008 AMC 10, 18
A right triangle has perimeter $ 32$ and area $ 20$. What is the length of its hypotenuse?
$ \textbf{(A)}\ \frac{57}{4} \qquad
\textbf{(B)}\ \frac{59}{4} \qquad
\textbf{(C)}\ \frac{61}{4} \qquad
\textbf{(D)}\ \frac{63}{4} \qquad
\textbf{(E)}\ \frac{65}{4}$
1967 AMC 12/AHSME, 11
If the perimeter of rectangle $ABCD$ is $20$ inches, the least value of diagonal $\overline{AC}$, in inches, is:
$\textbf{(A)}\ 0\qquad
\textbf{(B)}\ \sqrt{50}\qquad
\textbf{(C)}\ 10\qquad
\textbf{(D)}\ \sqrt{200}\qquad
\textbf{(E)}\ \text{none of these}$
2010 Germany Team Selection Test, 2
For an integer $m\geq 1$, we consider partitions of a $2^m\times 2^m$ chessboard into rectangles consisting of cells of chessboard, in which each of the $2^m$ cells along one diagonal forms a separate rectangle of side length $1$. Determine the smallest possible sum of rectangle perimeters in such a partition.
[i]Proposed by Gerhard Woeginger, Netherlands[/i]
2000 AIME Problems, 4
The diagram shows a rectangle that has been dissected into nine non-overlapping squares. Given that the width and the height of the rectangle are relatively prime positive integers, find the perimeter of the rectangle.
[asy]
defaultpen(linewidth(0.7));
draw((0,0)--(69,0)--(69,61)--(0,61)--(0,0));draw((36,0)--(36,36)--(0,36));
draw((36,33)--(69,33));draw((41,33)--(41,61));draw((25,36)--(25,61));
draw((34,36)--(34,45)--(25,45));
draw((36,36)--(36,38)--(34,38));
draw((36,38)--(41,38));
draw((34,45)--(41,45));[/asy]
Novosibirsk Oral Geo Oly VIII, 2017.4
On grid paper, mark three nodes so that in the triangle they formed, the sum of the two smallest medians equals to half-perimeter.
2003 AMC 12-AHSME, 11
A square and an equilateral triangle have the same perimeter. Let $ A$ be the area of the circle circumscribed about the square and $ B$ be the area of the circle circumscribed about the triangle. Find $ A/B$.
$ \textbf{(A)}\ \frac{9}{16} \qquad
\textbf{(B)}\ \frac{3}{4} \qquad
\textbf{(C)}\ \frac{27}{32} \qquad
\textbf{(D)}\ \frac{3\sqrt{6}}{8} \qquad
\textbf{(E)}\ 1$
2015 AIME Problems, 4
In an isosceles trapezoid, the parallel bases have lengths $\log3$ and $\log192$, and the altitude to these bases has length $\log16$. The perimeter of the trapezoid can be written in the form $\log2^p3^q$, where $p$ and $q$ are positive integers. Find $p+q$.
2019 AMC 8, 4
Quadrilateral $ABCD$ is a rhombus with perimeter $52$ meters. The length of diagonal $\overline{AC}$ is $24$ meters. What is the area in square meters of rhombus $ABCD$?
[asy]
unitsize(1cm);
draw((0,1)--(2,2)--(4,1)--(2,0)--cycle);
dot("$A$",(0,1),W);
dot("$D$",(2,2),N);
dot("$C$",(4,1),E);
dot("$B$",(2,0),S);
[/asy]
$\textbf{(A) } 60
\qquad\textbf{(B) } 90
\qquad\textbf{(C) } 105
\qquad\textbf{(D) } 120
\qquad\textbf{(E) } 144$
2005 Sharygin Geometry Olympiad, 11.2
Convex quadrilateral $ABCD$ is given. Lines $BC$ and $AD$ intersect at point $O$, with $B$ lying on the segment $OC$, and $A$ on the segment $OD$. $I$ is the center of the circle inscribed in the $OAB$ triangle, $J$ is the center of the circle exscribed in the triangle $OCD$ touching the side of $CD$ and the extensions of the other two sides. The perpendicular from the midpoint of the segment $IJ$ on the lines $BC$ and $AD$ intersect the corresponding sides of the quadrilateral (not the extension) at points $X$ and $Y$. Prove that the segment $XY$ divides the perimeter of the quadrilateral$ABCD$ in half, and from all segments with this property and ends on $BC$ and $AD$, segment $XY$ has the smallest length.
2013 Online Math Open Problems, 30
Pairwise distinct points $P_1,P_2,\ldots, P_{16}$ lie on the perimeter of a square with side length $4$ centered at $O$ such that $\lvert P_iP_{i+1} \rvert = 1$ for $i=1,2,\ldots, 16$. (We take $P_{17}$ to be the point $P_1$.) We construct points $Q_1,Q_2,\ldots,Q_{16}$ as follows: for each $i$, a fair coin is flipped. If it lands heads, we define $Q_i$ to be $P_i$; otherwise, we define $Q_i$ to be the reflection of $P_i$ over $O$. (So, it is possible for some of the $Q_i$ to coincide.) Let $D$ be the length of the vector $\overrightarrow{OQ_1} + \overrightarrow{OQ_2} + \cdots + \overrightarrow{OQ_{16}}$. Compute the expected value of $D^2$.
[i]Ray Li[/i]
2010 Stanford Mathematics Tournament, 6
A triangle has side lengths $7, 9,$ and $12$. What is the area of the triangle?
2002 Manhattan Mathematical Olympiad, 3
Let us consider all rectangles with sides of length $a,b$ both of which are whole numbers. Do more of these rectangles have perimeter $2000$ or perimeter $2002$?
2000 AMC 8, 16
In order for Mateen to walk a kilometer ($1000$m) in his rectangular backyard, he must walk the length $25$ times or walk its perimeter $10$ times. What is the area of Mateen's backyard in square meters?
$\text{(A)}\ 40 \qquad \text{(B)}\ 200 \qquad \text{(C)}\ 400 \qquad \text{(D)}\ 500 \qquad \text{(E)}\ 1000$
2006 AMC 10, 6
A region is bounded by semicircular arcs constructed on the side of a square whose sides measure $ 2/\pi $, as shown. What is the perimeter of this region?
[asy]
size(90); defaultpen(linewidth(0.7));
filldraw((0,0)--(2,0)--(2,2)--(0,2)--cycle,gray(0.5));
filldraw(arc((1,0),1,180,0, CCW)--cycle,gray(0.7));
filldraw(arc((0,1),1,90,270)--cycle,gray(0.7));
filldraw(arc((1,2),1,0,180)--cycle,gray(0.7));
filldraw(arc((2,1),1,270,90, CCW)--cycle,gray(0.7));[/asy]
$ \textbf{(A) }\frac {4}\pi\qquad\textbf{(B) }2\qquad\textbf{(C) }\frac {8}\pi\qquad\textbf{(D) }4\qquad\textbf{(E) }\frac{16}{\pi} $