I already got 842 squared=c2 I just need help with simplest radical form

Answer:
The answer is 29.
Step-by-step explanation:
The steps to do this :
[tex] {c}^{2} = {20}^{2} + {21}^{2} [/tex]
[tex] {c}^{2} = 841[/tex]
[tex]c = \sqrt{841} [/tex]
[tex]c = 29[/tex]