[tex]\sin \text{ A =}\frac{opposite}{\text{hypotenuse}}=\text{ }\frac{a}{c}[/tex]
In a right-angled triangle, the side facing the reference angle is the opposite side, the side facing the right angle is the hypotenuse
Since sinA= opposite/hypotenuse
opposite= a
hypotenuse = c
Thus, sinA= a/c
