Answer:
The length of the page inside the margins=8 3/4 inches
Explanation:
The total length of the year book can be expressed as;
L=l1+l2+l3
where;
L=Total length of yearbook
l1=top margin length
l2=inside margin length
l3=bottom margin length
In our case;
L=10 inches
l1=1/2 inches
l2=unknown
l3=3/4 inches
replacing;
10=(1/2)+l2+(3/4)
(1/2)+(3/4)+l2=10
(5/4)+l2=10
l2=(10)-(5/4)
l2=8 3/4 inches
The length of the page inside the margins=8 3/4 inches