Answer:
78 inches of ribbon does Mrs. Martin need
Step-by-step explanation:
Area of a rectangle (A) is given by:
.....[1]
where,
l is the length of the rectangle and w is the width of the rectangle.
As per the statement:
The area of the mirror is 324 square inches. The width of the mirror is 12 inches.
⇒A = 324 square inches and w = 12 inches.
By [1] we have;
![324 = 12l](https://tex.z-dn.net/?f=324%20%3D%2012l)
Divide both sides by 12 we have;
27 = l
or
l = 27 inches
We have to find the inches of ribbon does Mrs. Martin need.
Perimeter of the rectangle(P) = 2(l+w)
Substitute the given values we have;
![P = 2 \cdot (27+12) = 2 \cdot 39 = 78 in](https://tex.z-dn.net/?f=P%20%3D%202%20%5Ccdot%20%2827%2B12%29%20%3D%202%20%5Ccdot%2039%20%3D%2078%20in)
Therefore, 78 inches of ribbon does Mrs. Martin need