What is the approximate length of the diagonal of a square with side length of 20 centimeters

28.28 cm

Explanation:

a² + b² = c²

20² + 20² = c²

c² = 400 + 400

c² = 800

c = √800

c = 28.28 cm

You can either use the Pythagorean theorem or the formula d = a√2.

Pythagorean theorem:

The diagonal is the hypotenuse of the right triangle in the square and the two sides are the legs.

20² + 20² = d²
400 + 400 = d²
800 = d²
√800 = d
28.28 = d

Using the formula:

d = a√2
d = 20√2
d = 28.28

The answer with both the methods is the same.

Hope this helps :)