Aright rectangular prism is shown.

what is the length of df to the nearest tenth of a centimeter?

drag and drop the answer into the box.

So what you are looking for is the hypotenuse of the triangle DCF. 

We know DC is 3cm, so we need CF.

BC and CF and CF create a right triangle. 

Using Pythagorean Theorem, CF is about 10.2

Now using Pythagorean Theorem again, 3^2 +10.2^2=113

The sqaureroot of that is 10.6. So 10.6 is your answer