SOLUTION: The adjacent sides of a parallelogram are 21 cm and 13 cm .if one of the diagonal is 2√105 cm long .find the length of the other diagonal

Algebra ->  Parallelograms -> SOLUTION: The adjacent sides of a parallelogram are 21 cm and 13 cm .if one of the diagonal is 2√105 cm long .find the length of the other diagonal       Log On


   

Question 971793: The adjacent sides of a parallelogram are 21 cm and 13 cm .if one of the diagonal is 2√105 cm long .find the length of the other diagonal
Answer by Boreal(15235) About Me  (Show Source):
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x^2 + ((2sqrt(105)^2)=2 (21^2 + 13^2) 2 * (square of one side+ square of adj side)=2 (square of each diagonal added)
x^2 + 4(105) = 2 *(441 +169)
x^2 +420 =1220
x^2=800
x=20 sqrt (2)