Please help! Thank you

If a and b are the measures of two first quadrant angles and sin a = 4/9 and sin b = 2/5 find sin(a+b).

Brainliest ! which of the coordinates are not of th vertices of the feasible region for the system of inequalities y≤4,,x≤5,x+y> 6 a(2,4) b(0,6) c(5,4) d(5,1)

Janice determined there were 10 possible outcomes when tossing two coins and spinning a spinner numbered 1 through 6. what is the correct number? what might have been janice's error?