Question 1178565


Two Angles are Supplementary when they add up to {{{180}}} degrees.

let one angle be {{{alpha}}} and other {{{beta}}}

then we have:

{{{alpha + beta=180}}}

if  given that {{{alpha=2beta+9}}}, we have

{{{2beta+9+ beta=180}}}

{{{3beta=180-9}}}

{{{3beta=171}}}

{{{beta=171/3}}}

{{{beta=57}}}


then

{{{alpha=2*57+9}}}

{{{alpha=123}}}