Question 880991
General term, {{{4+(n-1)*2}}}.

Series, {{{(n/2)(4+4+(n-1)*2)=180}}}, and you can either derive the formula or refer to any suitable reference source.
{{{(n/2)(8+2n-2)=180}}}
{{{n(6+2n)=360}}}
{{{2n^2+6n-360=0}}}
{{{highlight_green(n^2+3n-180=0)}}}

{{{highlight((n-12)(n+15)=0)}}}
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TWELVE TERMS.