Answer:
16 cms.
Step-by-step explanation:
The length of each side = 40 / 4 = 10 cm (as the 4 sides of a rhombus are congruent).
If we draw the other diagonal we form 4 right angled triangles (another property of the rhombus - diagonals bisect each other at tight angles. ).
The side of the rhombus is the hypotenuse of the right triangle.
So if we consider one triangle:
10^2 = 6^2 + x^2 where x is half the length of the other diagonal.
x^2 = 10^2 - 6^2
x^2 = 100 - 36 = 64
x = 8 cm.
So the diagonal is 16 cms long.
