Respuesta :

Answer:

29 Hope this helps!

tsheringsamdrup200

its 29 m

Step-by-step explanation:

as a²= b²+c²

a²=(21)²+(20)²

a²=841

a=√841

a=29

here we need to consider the diagonal angle of the opposite corner that makes up the rectangle so the answer is 29 which is the diagonal length of the rectangle.