Answer:
B. 19.1cm
Explanation:
Perimeter of a square = 4 × length
Perimeter = 54cm
Perimeter of a square = 4 × length
54 = 4 × length
54 = 4l
Divide both sides by 4
l = 54 / 4
= 13.5cm
Find the length of a diagonal,
Diagonal = hypotenuse
Using Pythagoras theorem
Hypotenuse^2 = opposite^2 + adjacent^2
Opposite = adjacent in a square because of the equal length
Opposite = adjacent = 13.5cm
Hypotenuse^2 = opposite^2 + adjacent^2
= 13.5^2 + 13.5^2
= 182.25 + 182.25
Hypotenuse^2 = 364.5
Find the square root of both sides
√Hypotenuse^2 = √ 364.5
Hypotenuse = 19.09cm
To the nearest tenth = 19.1cm
B. 19.1cm