Answer:
I think its 12
Step-by-step explanation:
because these half angels are equal to 30,90, and 60
if you are looking for AD then we have half of 10 which is 5
So then we had 5+13=18
If we add 18+12 it will equal to 30
and if we add them all up 13+10+12+13=48
and acute angle-an angle can equal to anything below 90
I think this is correct
