Question 127402

since angles {{{DCA}}} and {{{BAC}}} have equal measures of {{{60}}} degrees and are {{{complementary}}}, then angles {{{DAC}}} and {{{BCA}}} have equal measures of {{{30}}} degrees

if we have  {{{DCA+ DAC = 90}}}, then angle {{{ADC}}} is {{{90}}} degrees

same for other two; so we have a square (or rectangle)