In the diagram, the lengths of four of the sides of the figure
are shown in terms of .
Assuming that , the
perimeter of the figure is
, 2022
Pick one
Solution
Because all of the angles in the figure are right angles, each
line segment is either horizontal or vertical.
The height of the figure is and the width of the figure is . This means that the length of the unmarked vertical segment must equal . Also, the length of the unmarked horizontal segment must equal . Starting in the top left corner and adding lengths in a clockwise direction, the perimeter is $x + 2x + x + x +
2x + 3x = 10x. Alternatively, we can "complete the rectangle" by sliding the shortest horizontal side and the shortest vertical side as shown to form a rectangle with height
3x2x: [[IMAGE0]] The perimeter of this rectangle is
2x + 2 3x = 10x$.
Want a route through all this instead of an archive? The track
puts 2,604 problems in a working order, from Junior Challenge level to the IMO shortlist.