Question

plz solve question 23 whose answer is =8

Answer 1

[(2n-4)×90°]/n - 360°/(n+1) =95°,

[(2n-4)(n+1)×18 - 72n]/[n(n+2)] =19°,


[(2n²-2n-4)×18 - 72n]/[n(n+1)] =19°,

[36n²-36n-72 - 72n]/[n(n+1)] =19°,


[36n²-108n-72] =19n²+19n,

36n²-19n²-108n-19n-72=0,

17n²-127n-72=0,

17n²-(136-9)n-72=0,

17n²-136n+9n-72=0,

17n(n-8)+9(n-8)=0,

(n-8)(17n+9)=0,

then

n-8=0,

n=8 (Octagon)