Answer:
D
Step-by-step explanation:
Triangle BDC is a right triangle (If you dont understand I can explain in depth). Since it's a right triangle, we can use the pythagorean theorem to find the length of BD. The pythagorean theorem states that the length of the smaller legs squared = the longest side squared. So we can set up the equation [tex]9^{2}[/tex]+[tex]x^{2}[/tex]=[tex]15^{2}[/tex] where x is the length of the missing side (BD). If we were to solve for x, (I think you should know how to do this but if not I can explain), you get 12
