Help pls I will give brainliest

Answer:
12cm
Step-by-step explanation:
This is a problem which can be solved with the pythagoras therom.
[tex]a^{2} +b^{2} =c^{2}[/tex]
Plus we can split this triangle into two triangles.
The split triangle has dimensions of 13(bc) by 5 cm(dc).[tex]a^{2} +b^{2} =c^{2}[/tex]
[tex]5^{2} +b^{2} =13^{2}[/tex]
Now we solve for b which is the lenght of bd
[tex]25 +b^{2} =169[/tex]
[tex]b^{2} =144[/tex]
[tex]b = \sqrt{144}[/tex]
[tex]b = 12[/tex]
Therefore the lenght of bd is 12cm
Hope this helps! :)