Answer: 4 / 5
Step-by-step explanation:
1) For a right triangle, the ratio sine is defined as:
sin(x) = opposite-leg / hypotenuse
2) x is the angle. In this case: A
3) As per the figure, the opposite leg to tha angle A measures 28
4) As per the figure, the hypotenuse measures 35
5) Calculations:
sin(A) = 28 / 35
Simplify dividing both numerator and denominator by 7 => 28/35 = 4/5