L3.1 - Scale Drawings

Author:Ms. Leon-Guerrero (Ms. LG)

Topic:Dilation

Learning Intentions and Success Criteria

We are learning to:

Comprehend the terms scale factor and dilation.
Critique and create scaled drawings of figures (using words and other representations).

We are successful when we can:

Dilate a figure given a scale factor and center.

1.1: Is That the Same Hippo?

Diego took a picture of a hippo and then edited it. Which is the distorted image? How can you tell?

Is there anything about the pictures you could measure to test whether there’s been a distortion?

1.2: Sketching Stretching

A dilation with center O and positive scale factor r takes a point P along the ray OP to another point whose distance is r times farther away from O than P is. If r is less than 1 then the new point is really closer to O, not farther away. 1. Dilate H using C as the center and a scale factor of 3. H is 4 cm from C.

2. Dilate K using O as the center and a scale factor of ¾. K is 4 cm from O.

1.3: Mini Me

1. Dilate the figure using center P and scale factor ½.

2. What do you notice? What do you wonder?

Are you ready for more?

1. Dilate the segment AB using center P by scale factor of 1/2. Label the result A'B'. 2. Dilate the segment AB using center Q by scale factor of 1/2. Label the result A'₁B'₁.