Answer
(a) $135.01°$
(b) $-408.27222°$
Work Step by Step
$1'=60''$
$1°=60'$
$1°=60'\times\frac{60''}{1'}=3600''$
(a) $135°~36''=135°+36''·\frac{1°}{3600''}=135°+0.01°=135.01°$
(b) $-408°~16'~20''=-(408°+16·\frac{1°}{60'}+20·\frac{1°}{3600''})=-(408°+0.27222)=-408.27222°$