Answer:
It is proved that if
is even the n is even.
Step-by-step explanation:
Given n is any integer.
To show
is even then n is even.
Proving by contrapositive suppose
is odd. Then we need to show n is odd.
Then, letting k is a ny integer,
Now since (2k+1) is odd therefore n is odd.
Conversly let n is odd, then,

since 2k+1 is odd so
is odd.
This proves, if n is even then
is even.
You can use the pythagorean theorem
15^2 = 225
17^2 = 289
225 + b^2 = 289
b^2 = 64
b = 8
so one half of one side is 8 so the whole side would be 16
hope this helps