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It looks like @mananth did not read the post, at all.
Otherwise, he (or she) would not write something IRRELEVANT to the problem.
I came to bring you the correct solution and the correct answer.
The diagonals of a rhombus (of any rhombus) cut it in 4 (four) congruent right-angled triangles.
One leg of such triangle is half of one diagonal.
The other leg of such triangle is half of the other diagonal.
So, you have 4 right-angled triangles with the legs of 7 and 8 units each.
Then the hypotenuse of each such a triangle is = = = 10.63 units (rounded).
It is the side length of any of 4 (four) sides of the rhombus. ANSWER
Solved.
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For your safety, ignore the post by @mananth, since it is IRRELEVANT to the problem.
As I just said several years ago, @mananth needs two helpers to work at this forum successfully:
- one assistant to read the problems to him (or to her) and explain their meaning,
- and the other assistant to edit and re-write his (or her) solutions after him (or her).
Currently, I alone perform the duties of these two assistants.
And I can not say that I am extremely happy of it . . .