Plane Geometry and Similarity Review

Consider triangle ABC. Triangle ABC is rotated 90º counterclockwise about the origin to form triangle A'B'C'. Which rule describes this transformation?

Find side length X.

• 16

• 18

• 2.4

• 15

What is the value of x?

• x = 2

• x = 10

• x = 16

• x = 54

Consider the right triangle. What is the approximate perimeter of the triangle?

• 17 units

• 18 units

• 28 units

• 40 units

Find the number of degrees in the third angle of the triangle

• 155

• 112

• 74

• 68

If  ABC ~  DEF and  DEF ~  GHI, then ______.

• AB = GH 

• ABC ~ GHI

• ACB~GHI

• BCA~GHI

Apply a dilation with a scale factor of ½ to triangle ABC. Let the image be triangle A’B’C’. Which one of the following equations is true?

• A’B’ = ½ (AB)

• AB = ½ (A’B’)

• m∠A’ = ½ (m∠A)

• m∠A = ½ (m∠A’)

A triangle is dilated about center O with a scale factor of  r=1.  How will the size of the image compare to the size of the pre-image?

• the image will be larger than the pre-image

• the image will be exactly the same size as the pre-image

• the image will be smaller than the pre-image

• the pre-image will be larger than the image

Find the length of segment EC to one decimal place.

• .5

• .2

• 19

• 22.9

The postulate or theorem that can be used to prove that the two triangles are similar is _____.

• SAS Similarity Theorem

• SSS Similarity Theorem

• AA Similarity Postulate

• ASA Congruence Theorem