Respuesta :
if the legs are length a and b and hyptonuse is c then
a²+b²=c²
so
if the legs are 20 and 21 and the hypotnuse is x then
20²+21²=x²
400+441=x²
841=x²
29=x
a²+b²=c²
so
if the legs are 20 and 21 and the hypotnuse is x then
20²+21²=x²
400+441=x²
841=x²
29=x
Answer: the correct option is (B) 29.
Step-by-step explanation: We are given to find the length of the hypotenuse x, if (20, 21, x) is a Pythagorean triple.
We know that
in a right-angled triangle, the lengths of the sides (hypotenuse, perpendicular, base) is a Pythagorean triple, where
[tex]Hypotenuse^2=Perpendicular^2+base^2.[/tex]
So, for the given Pythagorean triple, we have
[tex]x^2=20^2+21^2\\\\\Rightarrow x^2=400+441\\\\\Rightarrow x^2=841\\\\\Rightarrow x=\sqrt{841}~~~~~~~~~~~~~~~~~[\textup{taking square root on both sides}]\\\\\Rightarrow x=\pm29.[/tex]
Since the length of the hypotenuse cannot be negative, so x = 29.
Thus, the length of the hypotenuse, x = 29.
Option (B) is CORRECT.