Similarity

Dilations always preserve ____________.

• Lengths
• Angles
• Lengths and Angles
• Neither Lengths nor Angles

The measures of the angles in a triangle are 53⁰,78⁰, and 49⁰.  A similar triangle is created by using a dilation with a scale factor of 2.  What are the measures of the angles of this triangle?

• 53⁰,78⁰, and 49⁰
• There is not enough information to answer this question.
• 106⁰,156⁰, and 98⁰
• 26.5⁰,39⁰, and 24.5⁰

2 triangles are similar if _____________.

• their angles are congruent.
• their sides are congruent.
• their areas are equal.
• their perimeters are equal.

Are these triangles similar?
Angles in Triangle 1:  40⁰,60⁰, and 80⁰
Angles in Triangle 2:  40⁰,50⁰, and 90⁰

• Yes
• No
• There is not enough information to decide.

Tags

CCSS.HSG.SRT.A.2

AB = 4.  After a dilation, A'B' = 10.  What is the scale factor for the dilation?

• 5/2
• 10
• 4
• 2/5

Triangle ABC and XYZ are similar.  Use your knowledge of scale factor to find the length of X.

• 20
• 25
• 100
• 40

Solve for X.

• 2 ft
• 3 ft
• 4 ft
• 6 ft

Tags

CCSS.HSG.SRT.A.2

A triangle has sizes measuring 11 cm, 16 cm, and 16 cm. A similar triangle has sides measuring x cm, 24 cm, and 24 cm. What is x?

• x = 19 cm
• x = 24 cm
• x = 3 cm
• x = 16.5 cm

Tell whether the two figures are similar. Explain your reasoning.

• Yes, similar because they are the same shape and side lengths are proportional.
• No, not similar because they are the same shape, but side lengths are not proportional.
• Yes, same shape
• No, different sizes

Find the ratio (red to blue) of the perimeter.

• 11/6
• 6/11
• 121/36
• 36/121