Length of the side = 9 cm
Diagonal =
cm
Solution:
Area of the square = 81 square centimeters
In square all sides are equal.
Area of the square = side × side
Side × side = 81
Side² = 9² (∵81 = 9²)
Taking square root on both sides, we get
Side = 9 cm
Length of the side = 9 cm
To find the length of the diagonal:
In square all the angles are right angle.
Diagonal splits the square into two right angle triangle.
Using Pythagoras theorem,
In right triangle, square of the hypotenuse is equal to the sum of the square of the other two sides.
Here, diagonal is the hypotenuse.


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Taking square root on both side,
Diagonal =
cm