MathDB
2023 Fall Theme p3A

Source:

December 23, 2023
2023themeFAlLgeo

Problem Statement

A rectangular tea bag PARTPART has a logo in its interior at the point YY . The distances from YY to PTPT and PAPA are 1212 and 99 respectively, and triangles PYT\triangle PYT and AYR\triangle AYR have areas 8484 and 4242 respectively. Find the perimeter of pentagon PARTYPARTY.
Proposed by Muztaba Syed
Solution. 78\boxed{78} Using the area and the height in PYT\triangle PYT, we see that PT=14PT = 14, and thus AR=14AR = 14, meaning the height from YY to ARAR is 66. This means PA=TR=18PA = TR = 18. By the Pythagorean Theorem PY=122+92=15PY=\sqrt{12^2+9^2} = 15 and YT=122+52=13YT =\sqrt{12^2 +5^2} = 13. Combining all of these gives us an answer of 18+14+18+13+15=7818+14+18+13+15 = \boxed{78}.