Question

9^2=12^2+15^2-2•15^2•DC

DC=?

^2=La puterea a 2a

Answer 1

9^2=81  ; 12^2=144  ;  15^2=225  ;
=> 81 = 144+225 - 2*225*DC
     81 = 369 - 450*DC
    450*DC=369-81
    450*DC=288
           DC=288:450=0,64