Whats a proportion?

A proportion occurs when two ratios have to be equal to 

each other. 


For example: 

Also, it's always best to check and make sure that they're actually equal to each to each other. 

Identify Ratios of Corresponding Sides of Similar Triangles

To understand how to find x in similar triangles, you must understand what ratios and proportions are. 
A ratio is the comparison of two quantities. 
A proportion is an equation with a ratio on one side and an equal ratio on the other. 


When two triangles are similar, they have the same angles and their sides will be in the same proportion.

For example, 

and that's x, the missing side. (: 

How do we find the volume of cylinders?

The formula to find the volume of a cylinder is :
       v=bh

Example: 


In the example shown, you see that 10 is the base and 4 is the radius. Using the formula bxh you do it. Also remember that the base is pie times r^2. Which that gave us 16 pie. Then you multiply it by 10 the height, giving us 160 pie^3, in terms of pie.

Now is this different from surface area?

How do we do compositions of transformations? 3/7/13

Compositions of transformations, is the result of a second or more transformations performed on the image of the first transformation. It's important and necessary to always do the 2nd transformation first and then the first second.

For example:

1) What is the image of (-4,2) after R90 D3?

So first you the second transformation which is dilating (-4,2) by 3. All you do is multiply 3 by -4 & 2. Giving you : (-12, 6) 

Then having (-12,6) you do the first composition, which is Rotating it by 90
R90 -> (-y,x) 

So (-12,6) is (-6, 12) 
Answer: (-6,12) 

Question: What is the image(-12,6) after T(5,1) , R180?