Question

The perimeter of a square is 56cm. What is the approximate length of its diagonal?

1. 10.6
2. 14.0
3. 15.0
4. 19.8

Answer 1

4. 19.8
56/4=14
Diagonal of a square is equal to one side multiplied by the square root of two.
Therefore, it is 19.8, being that square root is (in super simple rounding) 1.5.

Answer 2

17.8 cm is the approximate length of its diagonal.

Explanation:

Side of the square = l

Perimeter of the square = P = 56 cm

Perimeter of the square is the sum of all the sides of the square.

4a = 56 cm

`4a=56 cm`

`a=(56)/(4)=14 cm`

The length of the diagonal is given by: d

`d^2=a^2+a^2` (Pythagoras theorem)

`d=√(a^2+a^2)=√(2a^2)`

`d=17.79 cm\approx 17.8 cm`

17.8 cm is the approximate length of its diagonal.