We have a garden that measures 17 feet by 20 feet. We want to pour cement for a 3-foot-wide sidewalk around the garden. To make the forms for the cement, we will need to buy some 2-by-4-inch lumber. How many feet of lumber will we need just for the perimeter of the walk? (Consider both the inside and outside perimeter.)
I drew a picture of a garden and a sidewalk being built around the outside. The height of the inside (garden) was 17 ft and the width was 20 feet. Then, I made a 3-foot corner around all four corners of the garden. So, the height of the exterior was 17 + 3 + 3 = 23 feet, while the width was 3 + 3 + 20 = 26 feet. So, the perimeter of the inside is 74 feet and the perimeter of the outside is 98 feet. I added these two to get 172 feet as the total perimeter. Inexorably, I deemed that 172 feet of lumber was needed for the perimeter of the walk. Is that safe to assume or am I misinterpreting the question/what it is asking for? I am getting a bit "tripped up" of the fact that the problem gave me that, "to make the forms for the cement, we will need to buy some 2-by-4-inch lumber."
If anyone else cares to work out the problem/verify my solution, that would be nice.