Question

choose the perimeter.

Explanation:

Step1: Determine the side - lengths.

The horizontal side - length is 5 cm and the vertical side - length is 5 cm.

Step2: Use the perimeter formula for a square.

For a square, the perimeter $P = 4s$, where $s$ is the side - length. Here $s = 5$ cm, so $P=4\times5$ cm.

Step3: Calculate the perimeter.

$4\times5=20$ cm.

Answer:

20 cm