The formula for the light bend would be n1*sin i= n2 * sin r
If you use "sin (90-x)= cos x" principle, you can change the sin in the equation into
n1*sin i= n2 * sin r
n1 * cos a= n2 * cos b
n2/n1= cos a/ cos b
Assuming the n constant is the ratio of the glass compared to water then the answer would be: cos a/ cos b
That’s 46 That’s The answer
8 can go into 71 seven times
Add 4 to boh sides
t/5+4-4=9+4
t/5+0=13
t/5=13
times 5/1 both sides
5t/5=5*13
1t=65
t=65