Answer:
Its C just got it right.
Step-by-step explanation:
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
Easy
the easiest way is to imagine that you have a rectangle with a corner cut off
the area of the figure=area of rectangle-area cut off
area that was cut off was a triangle
area of rectangle=length times width
area of triangle=1/2base times height
so we draw imaginary lines like in attachment
find area of rectangle
legnth=9 inch
width=9 inch
area=9 times 9=81 in^2
triangle
the top part is ?+5=9, so the base of triangle=4
the side is ?+4=9, so the base is 5
area=1/2 times 4 times 5=10 in^2
area=rectangle-triangle
area=81-10=71 in^2
Answer:
37.5 Units
Step-by-step explanation: