Ezekiel 43:16

And the altar hearth shall be twelve cubits long, twelve wide, square in its four sides.

Exodus 27:1

And you shall make an altar of acacia-wood, five cubits long and five cubits broad. The altar shall be square. And the height of it shall be three cubits.

Exodus 38:1-2

And he made the altar of burnt offering of acacia-wood. Its length was five cubits, and its breadth five cubits, square; and its height three cubits.

2 Chronicles 4:1

And he made an altar of bronze. Twenty cubits was the length of it, and twenty cubits its breadth, and ten cubits its height.

Ezra 3:3

And they set the altar on its bases, for fear was on them because of the people of those countries. And they offered burnt offerings on it to Jehovah, burnt offerings both morning and 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 shall make an altar of acacia-wood, five cubits long and five cubits broad. The altar shall be square. And the height of it shall be three cubits.
2 Chronicles 4:1
And he made an altar of bronze. Twenty cubits was the length of it, and twenty cubits its breadth, and ten cubits its height.
Ezra 3:3
And they set the altar on its bases, for fear was on them because of the people of those countries. And they offered burnt offerings on it to Jehovah, burnt offerings both morning and evening.

Square

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