math
posted by Jared .
A square is 7 meters on a side. To the nearest tenth of a meter, how long is the diagonal of the square?
A: 9.8
B: 9.9
C: 10.0
D: 14.0

The diagonal of a square forms two
454590 triangles.
The sides of a 454590 triangle are in the ratio,
a : b : hypotenuse
x : x : x(sqrt(2))
The diagonal is the hypotenuse of this 454590 triangle.
Side = 7
7 * (sqrt(2)) = ? 
a^2 + b^2 = c^2
7^2 + 7^2 = c^2
49 + 49 = 98
c = square root of 98
Be sure to round to the nearest tenth.