Answer
(a) $69^\circ 49'30''$
(b) $159^\circ 49'30''$
Work Step by Step
(a) For the complement, we have $\alpha=90^\circ-20^\circ 10'30''=89^\circ59'60''-20^\circ 10'30''=69^\circ 49'30''$
(b) For the supplement, we have $\beta=180^\circ-20^\circ 10'30''=179^\circ59'60''-20^\circ 10'30''=159^\circ 49'30''$
