Using Triangle Similarity Theorems (6) A
12
E A
B
9
D
What is the length of DC? Show work.

DC = 3

Step-by-step explanation:

Based on triangle similarity theorem, we would have the following equation:

Plug in the values

Cross multiply

3(9 + DC) = 9×4

27 + 3DC = 36

Subtract 27 from each side

3DC = 36 - 27

3DC = 9

Divide both sides by 3

DC = 9/3

DC = 3

c.   x=2.4cm

step-by-step explanation:

similar triangles are triangles which have the same shape but not the same size. this means their angle measures are equal but their side lengths are not instead they are proportional. to solve, we will set up a proportion and solve.

a proportion is two equal ratios set equal to each other. we form the ratios by finding corresponding sides (sides which match to each other on both triangles by their position). out ratios will be one side of the small triangle over the corresponding side on the big triangle as shown below:

.

to solve the proportion, we'll cross multiply by multiplying numerator with denominator across the equal sign.