12.7 Similar

Today we will… Return to the idea Of similar objects

Similar means same shape different size

Remember proportions ==

Now we do that with 3 dimensional objects Can be Height, radius Volume Surface area Lateral area width...

Scale factor The first object The Second object You will do this with sides, areas, volumes Then compare how the rates change

The scale factor for width of the prism on the left compared to the prism on the right is… 3 mm 2 mm 2 3

Now we can find the Scale for the surface area of the prism on the left compared to the one on the right. 3 mm 2 mm 2 3 Surface area is squared So the scale factor for surface are is the square of the width

So what will we do to find the scale factor of the volumes? 3 mm 2 mm 2 3 Volume is cubed So the scale factor for volume is the cube of the width

Given a scale factor for length, find the scale factors for Surface area and volume Area Volume 3 2

Let’s think If I double the radius … r What happens to the surface area? What happens to the Volume?

Chapter , 7-16 Chapter Review 1-28