Split - angle between diagonals in rectangle

[The Highlander]

And a square IS a rectangle.

A fact of which far too many primary school teachers are completely oblivious!

When I was in primary school (admittedly more than half a century ago ) my teachers had the good sense to refer to non-square rectangles as oblongs and, therefore, we had no problem happily accepting that squares and oblongs were both part of the same 'family' of rectangular figures.

Nowadays, when they come up to high school, we have to disabuse them of the notion that squares and rectangles are entirely separate plane figures and 'never the twain shall meet'. Unfortunately, however, too may Maths teachers fail to do this in the early years and so, I have often found S3 & S4 pupils still unaware of this fact at a stage when it can be important that they do know that a square is a rectangle!

(Just another of my pet hates. ?)

 

[Deleted member 4993]

A fact of which far too many primary school teachers are completely oblivious!

When I was in primary school (admittedly more than half a century ago ) my teachers had the good sense to refer to non-square rectangles as oblongs and, therefore, we had no problem happily accepting that squares and oblongs were both part of the same 'family' of rectangular figures.

Nowadays, when they come up to high school, we have to disabuse them of the notion that squares and rectangles are entirely separate plane figures and 'never the twain shall meet'. Unfortunately, however, too may Maths teachers fail to do this in the early years and so, I have often found S3 & S4 pupils still unaware of this fact at a stage when it can be important that they do know that a square is a rectangle!

(Just another of my pet hates. ?)

Same goes for ellipse and circle.

 

[Harry_the_cat]

Is an equilateral triangle an isosceles triangle?

 

[Steven G]

I taught many years at a community college. My worst majors were business major and math ed majors (future high school teachers). I never had a math ed major come into the college taking calculus 1. They all started off with either arithmetic of algebra. Exactly what did they learn in k-12 if they started off in arithmetic? Why would they want to teach math? Starting off with algebra is not much better. That just means that in k-12 they learned (some) arithmetic which is 5th grade level. They had absolutely no skills at all. It was so sad to see.

 

[The Highlander]

Is an equilateral triangle an isosceles triangle?

You're just scaring the pigeons again, Cat, aren't ya? ?
Your question is akin to that of the tree falling in the forest when there's nobody around to hear it! Whether or not it makes a sound depends on your definition (of sound: perception or vibrating air?) but the best response (IMNSHO) is another simple question: Is the Pope a Catholic? ??