2020 AMC 12A Problem 2

Below is the professionally curated solution for Problem 2 of the 2020 AMC 12A, from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2020 AMC 12A 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:Pythagorean Theoremdistance formula

Difficulty rating: 1020

2.

The acronym AMC is shown in the rectangular grid below with grid lines spaced 11 unit apart. In units, what is the sum of the lengths of the line segments that form the acronym AMC?

1717

15+2215 + 2\sqrt{2}

13+4213 + 4\sqrt{2}

11+6211 + 6\sqrt{2}

2121

Solution:

Split each letter into its segments. The AA is a diagonal of length 22,2\sqrt{2}, a vertical of length 2,2, and a crossbar of length 1.1.

The MM has two verticals of length 22 and two diagonals of length 2\sqrt{2} each. The CC is three sides of length 2.2.

The straight pieces total 2+1+2+2+2+2+2=13,2 + 1 + 2 + 2 + 2 + 2 + 2 = 13, and the diagonal pieces total 22+2+2=42.2\sqrt2 + \sqrt2 + \sqrt2 = 4\sqrt2.

The sum is 13+42.13 + 4\sqrt2.

Thus, C is the correct answer.

Problem 2 in Other Years