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

2 answers

The diagonal of a square forms two
45-45-90 triangles.

The sides of a 45-45-90 triangle are in the ratio,
a : b : hypotenuse
x : x : x(sqrt(2))

The diagonal is the hypotenuse of this 45-45-90 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.