What is the length of each side of a resonant dipole to receive 12MHz?

[amgc63]

TL;DR

I don’t understand why require to divide twice

Hi, a question:

Construct a resonant dipole to receive 12MHz.

Answer;

λ = c/f
= (3x10^8) / (12 x10^6)
= 25m
The dipole length λ/2 = 12.5m
The length of each side dipole is 12.5m/2 = 6.25m

Im confused, isn’t it the answer is 12.5m?
Why require to divide 12.5m/2 again to get the answer 6.25m?
Hope someone can explain.

Thanks in advance

 

[berkeman]

A half-wave dipole antenna is made up of two quarter-wave elements. A quarter-wave monopole antenna has one quarter-wave element over a ground plane...

https://www.antenna-theory.com/antennas/halfwave.php

 

[Baluncore]

A resonant half-wave dipole has a length of λ/2 because the transit return time of the wave, there and back, must be equal to the period of the wave. Half of a resonant half-wave dipole will be λ/4.