## Thursday, March 18, 2010

### Surface Area Growing Post

Hello, this assignment is a growing post about the surface area of basic 3-D objects. First there is a rectangular prism with a net that contains a problem that I will solve using formulas. Then a triangular prism problem, then a cylinder, after that is two videos showing how I solved it. Before that though, I have to show and solve the three basic 3-D objects below.
This is a rectangular prism with its net (sorry the pictures are bad). A rectangular prism has two squares and four rectangles (or 6 rectangles). Now onto the problem part.

Here's the problem. I need one formula for each side of the prism. However I will do one of each type of side since I am not doing the same side again with the same calculations (makes my life easier and this post shorter). For rectangles and squares, the formula is length (L = length in short) multiplied by width (W = width). Then I am going to put the measurements in for the rectangle (any way does not matter). You can use a calculator if you want for this question (I used one too). In this problem, there are only two shapes with different measurements.

10.2 by 7.4 Rectangles

Rectangle = L x W

Rectangle = 10.2 x 7.4

Rectangle = 75.48m squared

4.7 by 7.4 Rectangles

Rectangle = L x W

Rectangle = 4.7 x 7.4

Rectangle = 34.78m squared

Now after finding all of the areas of the rectangular prism, I will add all of the areas up to get the total surface area of the rectangular prism (what I am trying to find) to finish the problem. There are four 10.2 by 7.4 rectangles and two 4.7 by 7.4 rectangles.

75.48 + 75.48 + 75.48 + 75.48 + 34.78 + 34.78 = 371.48

TSA (Total Surface Area) = 371.48m squared

The next 3-D object is an triangular prism. It has two triangles and three rectangles.

#### 1 comment:

1. Good job Kris, well explained.