Answer:
[tex]7\sqrt{2} \ cm[/tex]
Step-by-step explanation:
Formula ………………………………………………
The length of a diagonal of a square with side of length “a” is :
[tex]a\sqrt{2}[/tex]
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Since a = 7 (in our case) then
[tex]\text{the length of the diagonal} =7\sqrt{2}[/tex]
Note : you can also use the Pythagorean theorem.