Question 578189
Complementary means the angle add up to 90 degrees
Let the angles be {{{a}}} and {{{b}}}
given:
(1) {{{ a + b = 90 }}}
(2) {{{ a/b = 2/7 }}}
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Multiply both sides of (2) by {{{ 7b }}}
(2) {{{ 7a = 2b  }}}
and
(1) {{{ b = 90 - a }}} 
Substitute this into (2)
(2) {{{ 7a = 2*( 90 - a ) }}}
(2) {{{ 7a = 180 - 2a }}}
(2) {{{ 9a = 180 }}}
(2) {{{ a = 20 }}}
and
{{{ b = 90 - a }}}
{{{ b = 70 }}}
The smaller angle is 20 degrees