GeoGebra Classroom

# Exploring Dilations

## PART 1 DIRECTIONS:

1) Select the slider tool to create a slider. Name the slider k. Set Min = -5, Max = 5, Increment = 0.1 2) Select the DILATE FROM POINT tool. Highlight a box around point A, point B, and Curious George's picture. Then select point C (to serve as center of dilation) In the pop-up box that appears, enter "k" (without the " " 's) to serve as the scale factor. 3) Select the Move tool. Explore! 4) Answer questions below APP

## QUESTIONS

What is the image of point A if k =4 ? What is the image of point B if k=-3 ? CHALLENGE Suppose point P = (a, b) is dilated about (0,0) with scale factor k. What would the coordinates of the image of P be? Express these coordinates in terms of a, b, and/or k. SWITCH JOBS !!!

## PART 2 DIRECTIONS:

1) Select the slider tool to create a slider. Name the slider t. Set Min = -5, Max = 5, Increment = 0.1 2) Select the DILATE FROM POINT tool. Highlight a box around point A, point B, and Curious George's picture. Then select point P (to serve as center of dilation) In the pop-up box that appears, enter "t" (without the " " 's) to serve as the scale factor. 3) Explore this new Applet. Please answer the questions that appear below the applet.

## 5)

If point A(4,3) was dilated about (3,0) with scale factor 3, what would be the coordinates of the image? If point B(10,2) was dilated about (4,-3) with scale factor -2, what would be the coordinates of the image? CHALLENGE Suppose point P = (a, b) is dilated about (c, d) with scale factor k. What would the coordinates of the image of P be? Express these coordinates in terms of c, d, a, b and/or k.