Categories: Continue
Date: Nov 7, 2008
Title: Real Life Geometry
Mr. Schumaker shows us how to use home improvement projects to teach our children geometry.
Come on. Admit it. You have a room in your house that you would just love to redecorate. Maybe it is the catch-all area you would like to turn into a guest room. Or it could be that horrible-looking carpeting and wallpaper you inherited from the previous owners. So how do you fit it into your busy schedule? Actually, it is a teachable moment waiting to happen. Make your remodeling project a unit study on applied geometry. For our example, we will use a room in my house that I plan to overhaul. This makes a nice example, because it is a simple rectangular room. We are not going to do the closet. (Out of sight; out of mind.)
Time to break out the yardsticks and measuring tapes. My room measured fourteen feet by thirteen feet six inches. For younger children, you can have them measure to the nearest foot, and for example, have them round up the thirteen feet six inches to fourteen feet. If you have older children, you can teach how to convert inches into fractions of a foot. There are twelve inches in a foot; six inches is 6/12 of a foot or ½ foot.
To find out how much paint you need for the ceiling, you now have to figure area. Length times width, or fourteen feet times thirteen ½ feet, is 189 square feet. According to the can, a gallon of interior latex paint will cover 400 square feet. On paper, it looks like a half gallon would do the whole ceiling. Time for our first reality check. That is assuming only one coat will do the job. Rather than have to make another trip to the store, many people will just go ahead and buy a full gallon of paint.
Most houses have eight-foot tall walls, but we live in an older home. So our walls are ten feet high. Although we have four walls, we only have to find two areas, because the opposite walls will be the same sizes. One area will be the length of the room times the height (fourteen times ten) which is 140 square feet. The other will be the width times the height (thirteen ½ times 10) which is 135 square feet.
So those two areas combined are 275. Toss in the matching mates, and two times 275 gives us a total area of 550 square feet. Take the total area divided by the 400 feet (what a can of paint will cover). That gives us one can of paint and a remainder of 150 square feet left to cover. Now there are a couple ways we can handle the extra 150 square feet. Rounding up is probably best, because if you don’t, the “remainder” will not get painted. Now your kids can understand why dad has so many half-empty cans of paint in the garage. (Half-full, if you are an optimist.)
Again we will have the same area as the ceiling, but figuring carpet is slightly different than calculating gallons of paint. Carpet is sometimes sold by the square yard. A yard is three feet long. If you have a square that is three feet on each side, that would be a square yard. Using our area formula, we discover that a square yard contains nine square feet. Now we take our area from Lesson one (189 square feet) and divide it by nine and get approximately twenty-two square yards.
Carpet is usually sold in twelvefoot- wide runs. Every three feet of run contains four square yards. Think about it. Since we have twenty-two square feet, let’s round up to the nearest multiple of four, which would be twenty-four, so we need six three-foot runs, or eighteen linear feet of carpet.
Will this really work? Second reality check: If we first ran our carpet along the 14 foot length of the room, we would be left with a one ½ foot by thirteen ½ foot section of floor left uncovered and only four linear feet of carpet left. So how are you going to handle it? You could buy double the length and have lots of waste, but at least you would have only one seam. Most stores have service people that are more than willing to give advice on this. Listen and choose the best way for you.
Let’s say we want to buy an elegant molding to trim the base of our walls. So far we have been dealing mainly with areas, it is now time to introduce the other important property of a rectangle—its perimeter. To find the perimeter, you add the length and the width together and then multiply the sum by two. So for our room, fourteen plus thirteen ½ is twenty-seven ½. That times two is fifty-five feet of molding.
Don’t worry about subtracting for doors. You are going to have to do some cutting, which will result in some waste. Many people add ten percent to account for waste. Ten percent of fifty-five is five ½. Add that to our total length and we have 60 ½ feet.
Third reality check: When you go to the store, molding only comes in specific lengths and you usually never find pieces that match up exactly to your walls. So try to get as close to 60 ½ feet as possible. Maybe a little over to be safe.
Now the question is, “Are you brave enough to try it?” Besides a nice room, your children will never ask you when will we ever use this “stuff” in real life.
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