2002 AMC 10A Problem 13

Below is the professionally curated solution for Problem 13 of the 2002 AMC 10A, from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2002 AMC 10A solutions, or check the answer key.

All of the real AMC 8, AMC 10, AMC 12, and AIME problems in our complete solution collection are used with official legal permission of the Mathematical Association of America (MAA).

Concepts:right trianglealtitudetriangle area

Difficulty rating: 1280

13.

The sides of a triangle have lengths of 15,15, 20,20, and 25.25. Find the length of the shortest altitude.

66

1212

12.512.5

1313

1515

Solution:

Since 152+202=225+400=625=252,15^2+20^2=225+400=625=25^2, the triangle is right with legs 1515 and 20,20, and area 12(15)(20)=150.\dfrac{1}{2}(15)(20)=150.

The shortest altitude falls to the longest side 25,25, and equals 215025=12.\dfrac{2\cdot 150}{25}=12.

Thus, the correct answer is B.

Problem 13 in Other Years