Dilations and Similarity

What is Dilation?

• Dilation means to enlarge or reduce a shape

• Dilation means to flip over a line

• Dilation means two figures that look alike

• Dilation means to make a shape smaller

State the coordinate of the image of point B (-10,-6) after a dilation with a scale factor of 1/2.

• (5,3)

• (20,12)

• (-20,-12)

• (-5,-3)

If two figures are similar, the corresponding angles are...

• Congruent

• Supplementary

• Proportional

• Different

How does a dilation change the angles of a polygon?

• It changes by the scale factor.
• Dilations do not change the angles.
• It is impossible to answer this question.  The angles change unpredictably.
• The angles all change to larger angles.

If two figures are similar, the corresponding sides are ______________.

• equal
• congruent
• proportional
• none of these

Solve for X.

• 2 ft
• 3 ft
• 4 ft
• 6 ft

Are these triangles similar, congruent or neither?

• Similar

• Congruent

• Neither

Are these triangles similar, congruent or neither?

• Similar

• Congruent

• Neither

Triangle PQR is the image of triangle JKL after a dilation. Is the dilation an enlargement or a reduction? Explain.

• Enlargement, because the image is larger than the original figure.

• Enlargement, because the image is smaller than the original figure.

• Reduction, because the image is smaller than the original figure.

• Reduction, because the image is larger than the original figure.

Are ABC and DEF similar?

• Yes

• No