# 1/11/16- Dilations on the Coordinate Plane

Warm-up

1. Amusement park A sells regular tickets for \$47 and a 3-day pass for \$130. Amusement park B sells regular tickets for \$52 and 3-day passes for \$140. Are the discounts at each park proportional to one another?

We then took notes on dilations and similarity:

Dilation– Non-rigid transformation (affects size) described using a scale factor and center of dilation. The preimage and image of a dilation are similar.

Similar- If two figures are similar, then all of their pairs of corresponding angles are congruent, and the ratios of their corresponding sides are proportional.

Ex.) ∆ABC ˜ ∆DEF (the ˜ means “is similar to”). Based off of the definition of similarity, we can say Angle A is congruent to Angle D, Angle B is congruent to Angle C, and Angle C is congruent to Angle F.

We could also say: AB/DE=BC/EF (ratios of corresponding sides are proportional- AB corresponds with DE, so we made a ratio between them).

We then worked through this worksheet: Dilations Practice Problems- Orange WS

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