Question 814520
C+A=90 and C+B=180.
ADDITIONALLY, A+B=202.


Note how the last equation does not contain C, but both of the first two equations do contain C.  Use them to eliminate C and then you will ...


{{{C=90-A}}}, and {{{C=180-B}}},
then {{{90-A=180-B}}},
{{{-A=180-90-B}}}
{{{B-A=180-90}}}
{{{B-A=90}}}


... have two equations in the unknowns, A and B.
{{{A+B=202}}} and {{{B-A=90}}}


Solving:
{{{A+B+B-A=202+90}}}
{{{2B=292}}}
{{{B=146}}}
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Study what has been shown, be sure you can follow it, and then finish the solution steps.