Question 845275
Complement = what you have to add to make a right angle (a {{{90^o}}} angle).
{{{drawing(300,300,-1,9,-1,9,
line(0,0,9,0),line(0,0,10,3.25),
line(0,0,0,9),arc(0,0,4,4,-18,0),
locate(2.1,0.9,18^o),rectangle(0,0,0.5,0.5),
red(arc(0,0,6,6,-90,-18)),locate(1,2.5,red(complement))
)}}} {{{complement=90^o-18^o=highlight(72^o)}}}
 
Supplement = what you have to add to make a straight angle (a {{{180^o}}} angle).
{{{drawing(300,200,-6,6,-1,7,
line(-6,0,6,0),line(0,0,10,3.25),
arc(0,0,4,4,-18,0),locate(2.1,0.9,18^o),
red(arc(0,0,6,6,-180,-18)),locate(-1.5,2.5,red(supplement))
)}}} {{{supplement=180^o-18^o=highlight(162^o)}}}