Similarity Proportionality and Geometric Mean

The two right triangles below are similar. What is x, the missing side length in triangle DEF? 

• 3.75

• 9.75

• 10

• 12

These 2 triangles are similar. Determine the value of x.

• x = 3

• x = 9

• x = 6

• x = 4

The triangles are similar, solve for the question mark.

• 8

• 12.5

• 18

• 24

Find side length X.

• 22.5

• 10

• 9

• 7.5

Find the length of DF, or state what additional information is needed to determine this length.

• To determine DF, we need the perimeter of both triangles

• To determine DF, we need the length of DE

• DF = 7

• DF = 5

Mathematical Equivalence

ON

Are the triangles similar?

• Yes

• No

What is the similarity statement for the triangle pair?

• ΔXYZ~ΔNEW

• ΔXZY~ΔNWE

• ΔZYX~ΔENW

• ΔYZX~ΔNWE

The ratio of the lengths of the corresponding sides of similar polygons

• Ratio

• Similar triangles

• Scale factor

• Angle Bisector Theorem

Determine the scale factor

• 1/5

• Not Similar

• 4/5

• 1/4