Answer:
[tex]220[/tex] cm
Step-by-step explanation:
We need to find the perimeter of the rectangular blanket in this case because a border is being sewn onto the blanket. The perimeter of a rectangle can be calculated by multiplying the sum of the rectangle's length and width by 2. As an algebraic expression, that would be [tex]2(l+w)[/tex], where [tex]l[/tex] is the rectangle's length and [tex]w[/tex] is the rectangle's width. We are given that [tex]l=70[/tex] and [tex]w=40[/tex]. Therefore, [tex]2(70+40)=2*110=220[/tex] cm of ribbon will be needed. Hope this helps!