Answer:
29 = c
Step-by-step explanation:
Since this is a right triangle we can use the Pythagorean theorem
a^2+b^2= c^2 where a and b are the legs and c is the hypotenuse
20^2 + 21^2 = c^2
400 +441 =c^2
841 = c^2
Take the square root of each side
sqrt(841) = sqrt(c^2)
29 = c
