Irene R. answered 04/14/20
Mechanical Engineer with 13+ years of Teaching Experience
Hi Ayanna,
This problem can be solved by creating an equation and solving it to find the width of the billboard.
Let's use the variable w to represent the width of the billboard.
Then we can write the following expression to represent the length of the billboard: w + 7
Since the perimeter of a rectangle can be calculated by adding 2 times the length to 2 times the width , we can write the following equation for the perimeter (P) of the billboard:
P = 2 • length + 2 • width
138 = 2 • (w + 7) + 2 • w
Now use the distributive property, combining like terms, and inverse operations to determine the value of w:
138 = 2w + 14 + 2w
138 = 4w + 14
138 - 14 = 4w + 14 - 14
124 = 4w
124/4 = 4w/4
31 = w
The width if the billboard is 31 inches.
The length will be 31 + 7 = 38 inches
To verify:
Perimeter = 2 • 38 + 2 •31 = 76 + 62 = 138 inches
Hope this helps Ayanna. Let me know if you have further questions or would like to schedule a lesson (online is available if you prefer). Take care.