Ezekiel 43:16

And the altar hearth [was] {twelve} [cubits] [in] length and {twelve} [cubits] [in] width; [it was] {squared on its four sides}.

Exodus 27:1

"And you will make the altar of acacia wood, five cubits long and five cubits wide; the altar will be square, and its height [will be] three cubits.

Exodus 38:1-2

And he made the burnt-offering altar of acacia wood; its length [was] five cubits, and its width [was] five cubits--[it was] square--and its height [was] three cubits.

2 Chronicles 4:1

And he made an altar of bronze, twenty cubits [was] its length, and twenty cubits [was] its width, and ten cubits [was] its height.

Ezra 3:3

They set up the altar on its foundations, because {they were in terror} because of the peoples of the lands. And they offered burnt offerings on it for Yahweh, burnt offerings for the morning and the evening.

Treasury of Scripture Knowledge

Summary

And the altar shall be twelve cubits long, twelve broad, square in the four squares thereof.

Square

Bible References

Twelve cubits

Exodus 27:1
"And you will make the altar of acacia wood, five cubits long and five cubits wide; the altar will be square, and its height [will be] three cubits.
2 Chronicles 4:1
And he made an altar of bronze, twenty cubits [was] its length, and twenty cubits [was] its width, and ten cubits [was] its height.
Ezra 3:3
They set up the altar on its foundations, because {they were in terror} because of the peoples of the lands. And they offered burnt offerings on it for Yahweh, burnt offerings for the morning and the evening.

Square

Exodus 38:1
And he made the burnt-offering altar of acacia wood; its length [was] five cubits, and its width [was] five cubits--[it was] square--and its height [was] three cubits.