## Saturday, March 6, 2010

### Brianna's Growing Post

In my post I will show you how to find the total surface area of a right triagular prim, a rectangular prism, and a cylinder.

Starting with the Triangular prism:

b=2.3m
h=1.4m

To find the the area of the triangles, you use the formula: bxh/2

bxh/2=A

2.3x1.4/2=A

3.2m2=A

The rectangles in this shape all have different areas.

In this shape there are three rectangles.

The formula that you use to find the area of rectangles is LxW=A.

This the first rectangle.

The second rectangle:

The third rectangle:

To find the total surface are, you add up the area of each shape:

TSA=3.2m+1.61m+0.98+1.87+3.2m

TSA=10.86 m squared

This is how you find the total surface area of a rectangular prism:

To find the total surface area of a rectangular prism, you have to find the area of three sides of the prism; the top, the side, and the front views.

The top view is equal to the bottom of the prism.

The front view is the same as the back.

To find the total surface area, you have to add up the area of each side.

TSA=21+21+43.05+45.05+73.8+73.8

TSA=275.7cm squared

There are two ways to find the total surface area of a cylinder:

Height=22cm

The first way of finding the total surface area of a cylinder is using the following formula:

The second way of finding the total surface area of a cylinder:

First you have to find the circumference of the circle. In this question you are given the radius so you have to find the diameter using this formula: rx2=d.

Then you multiply the diameter by pi to get the circumference.

The circumference of the circle is the rectangle's length. So to find the area of the rectangle, you use the formula LxW=A.

To find the area of a circle, you use the formula pi mulitipiled by r squared.

To find the total surface area of a cylinder, you add up the areas of the circles and the rectangle.

Hope I did this all right, please comment :)