I’m not quite sure how to answer this question.

When two shapes are mathematically similar, that means that all their sides are in a proportion.

We know the sieds of EH and AD, and so we can find the proportion of the shapes using these two sides.

EH/AD = 6/9 = 2/3

The ratio of EFGH to ABCD is 2:3

Now we have to find BC.

Becuase they're in proportion, we can form this equation:

=

Cross multiply:

24 = 2*BC

Divide both sides by 2:

BC = 12 cm

Good luck!

I need a easier question am trying to help people and get starts cause am new-

Step-by-step explanation: