45
MD^2+CD^2=CM^2
MD^2+BD^2=BM^2
CM^2-BM^2=CD^2-BD^2
AC^2=AD^2+CD^2
AB^2=AD^2+BD^2
CD^2-BD^2=AC^2-AB^2=9*9-6*6=45
CM^2-BM^2=45
45
MD^2+CD^2=CM^2
MD^2+BD^2=BM^2
CM^2-BM^2=CD^2-BD^2
AC^2=AD^2+CD^2
AB^2=AD^2+BD^2
CD^2-BD^2=AC^2-AB^2=9*9-6*6=45
CM^2-BM^2=45