Answer:
57.6°
Step-by-step explanation:
It is always helpful to draw a picture. Also, you need to memorize all the definitions of the trig functions. For example,
sine of an angle = opposite side/hypotenuse
In your case, SQ is opposite side to angle R and QR is the hypotenuse
Therefore, sin R = 6.5/7.7
m∠R = arcsin (6.5/7.7) = 57.6°
