How tall

[English4everyone]

Do we have to use the words in bold at the end of the answers? Or are they optional?
How tall are you? I am 2 meters tall.
How heavy are you? I am 55 kilograms heavy.
How big is your house? It is 80 square meters big.
And ...

[emsr2d2]

Do we have to use the words in bold at the end of the answers, or are they optional?

How tall are you? I am 2 meters tall.
Optional. In BrE, I would say "I'm five foot five".

How heavy are you? I am 55 kilograms heavy.
We don't normally ask people "How heavy are you?" as that implies they are heavy, not light, which might be taken as an insult. The question is "How much do you weigh?" and the answer would be "I weigh ten stone six" or "I weigh 55 kilos".

How big is your house? It is 80 square meters big.
No. "Big" is unnatural here. "My house is/measures eighty square metres". Although "How big is your house?" is used regularly it also suggests that the house is big, rather than small. A better question would be "What size is your house?"

And ...

See above.