If adjacent sides of a parallelogram are equal and one of the diagonals is equal to any one of the sides of the parallelogram, then AC : BD = ⎷3 : 1.
step by step explanation:
As ABCD is a parallelogram,
Therefore, AB=CD and BC=AD
Now, according to the question AB=BC,
Therefore, AB=BC=CD=AD
Hence, ABCD is a rhombus.
Now, as one of the diagonals is equal to its sides, therefore, AB=BC=CD=AD=BD
Let's assume AB=BC=CD=AD=BD=a
As, BD=a,
⇒ BO=a/2 (Since, in a rhombus diagonals bisect each other at right angle)
Hence, △AOB is right-angled at O.
Now, apply the Pythagoras theorem on △AOB,
⇒ AB2 = BO2 + AO2
⇒ a2 = (a/2)2 + AO2
⇒ AO2 = a2 - a2/4
⇒ AO2 = 3a2/4
⇒ AO = a⎷3/2
As AO = a⎷3/2, therefore AC = 2AO = a⎷3 units.
Therefore, the length of the diagonals are AC = a⎷3 units and BD = a units.
The ratio of the diagonals is:
AC/BD = a⎷3/a
= ⎷3/1
Therefore, AC : BD = ⎷3 : 1.