88 degrees is the answer. You would start by setting up the equation as (5x+7)+(8x+8)+(3x+5)=180 because all angles of a triangle have a sum of 180 degrees. From there you combine like terms which would leave the answer of being 16x+20=180 then you subtract the 20 from 180 to get x by itself. Then that would leave you with 16x=160 then you divide both sides by 16 to get x=10. From there you plug 16 into the x in the planetarium equation which is 8(10)+8 which equals 88 degrees