Answer:
The lenght of the diagonal is 7.1cm
Explanation:
First we have to calculate how much each side of the square measures
p = perimeter = 20cm
s = side
p = 4 * s
we replace with the known values
20cm = 4 * s
20cm / 4 = s
5cm = s
Each side of the square measures 5cm
To calculate one side of a right triangle from the other 2 sides we have to use Pythagoras
h = hypotenuse
a = leg 1 = 5cm
b = leg 2 = 5cm
h² = a² + b²
we replace the known values
h² = (5cm)² + (5cm)²
h² = 25cm² + 25cm²
h² = 50cm²
h = √(50cm²)
h = 7.07cm
Round to the nearest tenth
h = 7.07cm = 7.1cm
The length of the hypotenuse is 7.1cm
The hypotenuse of the triangle is the diagonal of the square