Answer:
16 cm
Step-by-step explanation:
Since all sides of a square are equal
Side x can be gotten using pythagoras theorem
- hypothanous² = adjacent² + opposite²
- [tex] {20}^{2} = \: {12}^{2} \: + \: {x}^{2} \\ 400 \: = \: 144 \: + \: {x}^{2} \\ {x}^{2} \: = \: 400 \: - \: 144 \\ {x}^{2} \: = 256 \\ x = \sqrt{256} \\ x = 16cm[/tex]
