Diagonal of square would have length 24. You can treat diagonal as leg of isosceles triangle.
Recall that 45-45-90 isosceles triangle has side ratio 1:1:√2 and so ratio of triangle sides would be 12√2 : 12√2 : 24 (you just multiple ratio by 12√2)
So then sides would be 12√2
Area would be (12√2)² = 288
So answer is 288 cm²
