Maths Olympiad Prep

Library / /180 of 482

, 2022

Algebra Difficulty 1.2 Junior Find the answer Canada

In the diagram, the lengths of four of the sides of the figure
are shown in terms of xx.Figure 0Assuming that x0x \neq 0, the
perimeter of the figure is

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 3x3x and the width of the figure is 2x2x. This means that the length of the unmarked vertical segment must equal 3xx=2x3x - x = 2x. Also, the length of the unmarked horizontal segment must equal 2xx=x2x - x = x. 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

Figure for this problem3xandwidth and width 2x: [[IMAGE0]] The perimeter of this rectangle is

Figure for this problem2×2\times 2x + 2 ×\times 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.

Source: CEMC, University of Waterloo, licensed CC-BY-NC-4.0. Statement reproduced verbatim; metadata (topic, difficulty) added by this project.