-24 - I didn’t explain it in words, but the step by step is in the image!
It appears as if 12cm is half the length of the side so we can assume that the total length of one side is 24cm.
The area of a square is given by the equation
where s is the length of the side.

A=576
The area of this square is 576cm2.
Hope this helps!
Answer:5
Step-by-step explanation:
5√2 · 9√6
Simplify.
5 × 9 √ 2 x 6 ⇒ Multiply 2 × 6.
5 × 9 √12
Simplify √12 to 2√3.
5 × 9 × 2√3 ⇔ Multiply
90√3
Therefore, the <u>correct alternative</u> is <u>option "B".</u>