the diagonals of a rhombus are 6cm and 8cm. find the length of a side of the rhombus.

Let ABCD be rhombus 
Let AC = 6 and BD = 8 
property Diagonals of rhombus bisect each other in right angle. 
consider AC and BD meet at O 
THen in triangle AOD 
AD² = AO² + OD² 
= (AC/2)² + (BD/2)² 
= 3² + 4² 
= 25 
AD = √25 
AD = 5 
the length of a side of the rhombus is 5cm