MathDB
Dihedral Group of Order 30

Source: 2015 AMC12B #7

February 26, 2015
symmetryAMC

Problem Statement

A regular 1515-gon has LL lines of symmetry, and the smallest positive angle for which it has rotational symmetry is RR degrees. What is L+RL+R?
<spanclass=latexbold>(A)</span>24<spanclass=latexbold>(B)</span>27<spanclass=latexbold>(C)</span>32<spanclass=latexbold>(D)</span>39<spanclass=latexbold>(E)</span>54<span class='latex-bold'>(A) </span>24\qquad<span class='latex-bold'>(B) </span>27\qquad<span class='latex-bold'>(C) </span>32\qquad<span class='latex-bold'>(D) </span>39\qquad<span class='latex-bold'>(E) </span>54