Determining Similarity of Triangles by Examining Corresponding Parts

This lesson teaches how to determine if two triangles are similar by examining their corresponding parts. It covers similarity transformations such as translation, reflection, rotation, and dilation, and explains how these transformations affect the shape and size of polygons. The lesson also discusses the properties of similar triangles, including proportional sides and congruent angles. An example is provided to demonstrate how to determine similarity using parallel lines and angle congruence. The lesson concludes by affirming that knowing three pairs of congruent angles is sufficient to establish triangle similarity.

Which transformation is unique in that it changes the size of a polygon?

• Translation

• Reflection

• Rotation

• Dilation

What is true about the corresponding angles of similar triangles?

• They are proportional.

• They are supplementary.

• They are congruent.

• They are complementary.

If triangle ABC is similar to triangle DEF, which of the following is true about their sides?

• All sides are parallel.

• Corresponding sides are proportional.

• Corresponding sides are congruent.

• All sides are equal.

How can you confirm the similarity of two triangles if you only know their angles?

• By measuring the sides to check proportionality.

• By ensuring all angles are congruent.

• By checking if all angles are right angles.

• By ensuring all angles are acute.

What is the approximate ratio of the sides if AT is 15 cm and UN is 11 cm?

• 0.67

• 0.73

• 0.85

• 0.80