一个凸n边形各内角的弧度数成等差数列,最小角为2π/3,公差为π/36,求边数n

Question

一个凸n边形各内角的弧度数成等差数列,最小角为2π/3,公差为π/36,求边数n

Answer 1

[2*2π/3+(n-1)*(π/36)]*n/2=(n-2)π
n^2-25n+144=0
n=16或9