Answer:
B, 4
Step-by-step explanation:
To do this you can use the Pathagaryos thereom a^2+b^2=c^2
So we have (x-2)^2+x^2=20
We can expand (x-2)^2 and get
x^2-4x+4
so we have x^2 -4x +4 + x^2=20
We can combine like terms and subtract 20 from both sides to get
2x^2-4x-16=0
We can factor this and get (2x+4)(x-4)
which means that x=4 and -2
Obviously the length can't be a negative and so we reject x= -2 and we get x=4
We can double check it and see that
(4-2)^2+4^2=20
and it does
