Geometry Review: Dilations

• 20°

• 40°

• 60°

• 80°

Triangle A'B'C' is the image of ΔABC after a dilation centered at the origin. The coordinates of the vertices of ΔABC are A(-2, 1), B(2,4), and C(2,−3). If the coordinates of A' are (−4,2), the coordinates of B' are

• (8,4)

• (4,8)

• (4,−6)

• (1,2)

If ΔTAP is dilated by a scale factor of 0.5, which statement about the image, ΔT'A'P', is true?

• 2AB = AD

• AD ⊥ DE

• AC = CE

• BC ∥ DE

Triangle KLM is dilated by a scale factor of 3 to map onto triangle DRS. Which statement is not always true?

• ∠ K ≅ ∠ D

• The area of triangle DRS is 3 times the area of triangle KLM.

• The perimeter of triangle DRS is 3 times the perimeter of triangle KLM.

A triangle is dilated by a scale factor of 3 with the center of dilation at the origin. Which statement is true?

• The area of the image is nine times the area of the original triangle.

• The perimeter of the image is nine times the perimeter of the original triangle.

• The slope of any side of the image is three times the slope of the corresponding side of the original triangle.

• The measure of each angle in the image is three times the measure of the corresponding angle of the original triangle.

In the diagram below, △ABE is the image of △ACD after a dilation centered at the origin. The coordinates of the vertices are A(0,0), B(3,0), C(4,5,0), D(0,6), and E(0,4). The ratio of the lengths of BE to CD is

On the set of axes below, △RST is the image of △ABC after a dilation centered at point P. The scale factor of the dilation that maps △ABC onto △RST is

• 2

• 3

• 2 and the origin

• 2 and vertex A