Respuesta :

Elkom
Apply the Pythagorean theorem:
[tex] {a}^{2} + {b}^{2} = c ^{2} [/tex]
[tex]{c}^{2} = {20}^{2} +{21}^{2} \\ {c }^{2} = 400 + 441 \\ {c}^{2} = 841 \\ \sqrt{ {c}^{2} } = \sqrt{841} \\ c = 29[/tex]