# Dilations Help

• Dec 11th 2007, 08:54 AM
bernardwbs
Dilations Help
Find image of (-15,13) for a dilation with the center (-1,-9) and a scale factor of 1/4.

We are stuck on these problems, and are having a tough time finding a way to solve with the resources we have. Any help would be very much appreciated.

Thank You,

Dennis Bernard
• Dec 11th 2007, 12:39 PM
earboth
Quote:

Originally Posted by bernardwbs
Find image of (-15,13) for a dilation with the center (-1,-9) and a scale factor of 1/4.

We are stuck on these problems, and are having a tough time finding a way to solve with the resources we have. Any help would be very much appreciated.

Thank You,

Dennis Bernard

Hello,

make a sketch (see attachment)

Use similar triangles. All distances can be calculated by the coordinates of the 2 points.
• Dec 18th 2007, 02:40 PM
JaneBennet
Alternatively, first do a translation of (1,9), apply a dilation of 1⁄4 with the origin as the centre, then translate back to (−1,−9). So

$(-15,13)\ \rightarrow\ (-14,22)\ \rightarrow\ (-3.5,5.5)\ \rightarrow\ (-4.5,-3.5)$