I believe the answer is A
by pythagorean formula, the last side is √(61)
by cos rule
cos A

A = 39.81
Since 2 croissants = $3 we can work out that 1 croissant = $1.50
Multiply $1.50 by 31 and we get $46.50
Therefore 31 croissants is $46.50
y = 4
first note that the right side simplifies to 12, equation can be written
= 12 ( multiply both sides by 0.8 )
2y + 1.6 = 9.6 ( subtract 1.6 from both sides )
2y = 8 ( divide both sides by 2 )
y = 4