We know that
in a right triangle
Applying the Pythagoras Theorem
c²=a²+b²
in this problem
c=√87 yd
a=√23 yd
b=?
so
b²=c²-a²-----> b²=(√87)²-(√23)²----> b²=87-23----> b²=64----> b=8 yd
the answer is
8 yd
Four times a number is equal to negative eight.
About 10 songs because if you add up all ten numbers of all the songs then you divide, then you divide again you will get 10 songs