Geometry-brackets to denote Area?? (AoPS)

[Jen500]

Is this standard notation? I have never learned this and I don't see it in the other two Geometry books we have.

For example, AoPS uses [ABC]=64 to mean the area of triangle ABC=64.

[regentrude]

I have never seen this elsewhere either.

But I do not recall ever seeing any other symbol to denote area this concisely.

[mathmarm]

As a loose-rule, you can use any symbol you want to denote any thing in math, so long as you define it first. Clearly, you'd want to do this with in reason, but you can use it in a more anti-traditional sense if you wanted to, so long as you defined everything within the scope of your writing and are consistent through-out.

 

I have seen [ABC] used to speak of area.

[JumpedIntoTheDeepEndFirst]

For what it is worth-they use this notation as early as the Pre-Algebra book. 

 

It took me a minute to figure it out but perhaps it helps end the confusion of what "A=" means which was how we always denoted area in geometry class (back in the mists of prehistory that is...)

[Luckymama]

For what it is worth-they use this notation as early as the Pre-Algebra book.

 

It took me a minute to figure it out but perhaps it helps end the confusion of what "A=" means which was how we always denoted area in geometry class (back in the mists of prehistory that is...)

Yeah, no more A with an awkward subscript! The brackets make it so easy to denote any type of area, including irregular polygons.

[daijobu]

I'm not fond of AOPS's brackets to denote area.  I prefer a subscript under the "A" to denote what I'm finding the area of.

 

For example A_square=s²

 

^{or sometimes I use a picture of the shape in the subscript or in parentheses:}

 

A_O=pi*r²

 

I find while teaching this to be easier to communicate than naming the vertices.  And it's easier to keep track of everything when you are adding and subtracting areas, like the area of a square less it's inscribed circle:

 

A_{square -} A_{O =} s^{2 -} pi*r²