What was the total size of the temple that King Herod built?
Herod did not build the Temple; he extensively refurbished it.
It (the second Temple) had already been standing for centuries by
his time.
The Temple itself as reconstructed by Herod was of the same
dimensions as that of Solomon: 60 cubits long, 20 cubits wide, and
40 cubits high (each cubit is about one-half meter, or one and
one-half feet). This space was divided into the Holy of Holies and
the heichal. The former measured 20 x 20 cubits, while the latter
was 20 x 40. Side-structures, as in Solomon's Temple, afforded
space for three stories of chambers on the north, south, and west
sides of the Temple. These chambers were connected by doors; and
trapdoors afforded access from those of one story to those of the
story immediately above or below. The whole breadth of the
structure including the side-buildings was 70 cubits.
East of Herod's Temple there was, as in Solomon's, a porch, 100
cubits wide, 100 cubits high, and 20 cubits deep, thus extending 15
cubits on either side of the Temple. Its gateway was 20 cubits
broad and 70 cubits high.
While (as mentioned above) Herod didn't change the dimensions of
the Temple itself, he did enlarge the Temple Mount and its outer
walls, which were some 900 cubits long on each side.