ABCD is a rhombus whose diagonals interesct at O. If AB=10 cm, diagonal BD = 16 cm, find the length of diagonal AC.


We know in rhombus diagonals bisect each other at right angle.


In ΔAOB


BO =


Using pythagorous theorem in ΔAOB


AB2 = AO2 + BO2


102 = AO2 + 82


100-64 = AO2


AO2 = 36


AO = = 6cm


Therefore length of diagonal AC of rhombus ABCD is 6 × 2 = 12cm.


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