Answer:
C= 14
Explanation:
The side is the square root of the area
S × S = A
S = √98
The diagonal is the hypotenuse of a right triangle formed by the two sides so
a² + b² = c²
Where C = the diagonal A = √98 , B = √98
so C²= (√98)² + (√98)²
This gives: C²= 98 + 98 or
C² = 196
√C² = √196
C= 14