Respuesta :

29! The missing length is 29. You can do the Pythagorean Theorem to solve this.

a^2 + b^2 = c^2
20^2 + 21^2 = c^2
841 = c^2 <—now take the square root
29 = c

The final answer:

c=29

Step-by-step explanation:

(21^2+20^2)

(441+400)

[tex]\sqrt{841}[/tex]

= 29