Let's take a triangle ABC, with a, b, and c the sides length, he law of sine is:
a/sin A =b/sin B = c/sin C
If we know the value of 2 angles and one side or the value of 2 sides and one angle, we can calculate all the elements of the triangle
Answer:

Step-by-step explanation:
We have the four thickest books from the line plot given by
Two books of
inch thick and the two books of
inch thickness.
So when the two
inch thick book is being piled on the top of a
inch thick books.
Therefore, the total thickness of the pile of books is given by :



Therefore, the thickness of the pile is
.
The length of the arc is 1.06m. hope that helps!