Math Mnemonics For Geometry

A collection of math mnemonics for geometry - to help you to remember various math facts, formulas and figures pertaining to geometry.

Geometry

Value Of Pi (π)
Count the number of letters in each word:

Pi (π) to 7 decimal places: (Word lengths are digits)
May I have a large container of coffee?
3.1415926

Pi (π) to 10 decimal places: (Word lengths are digits)
May I have a large container of coffee ready for today?
3.1415926535

Pi (π) to 12 decimal places: (Word lengths are digits)
See, I have a rhyme assisting my feeble brain, its tasks oft-times resisting.
3.141592653589

Pi (π) to 30 decimal places: (Word lengths are digits)
Now I, even I, would celebrate
In rhymes unapt, the great
Immortal Syracusan, rivaled nevermore,
Who in his wondrous lore,
Passed on before,
Left men his guidance
How to circles mensurate.

and another one also to 30 decimal places (written by Michael Shapiro)

Now I will a rhyme construct
By chosen words the young instruct.
Cunningly devised endeavour,
Con it and remember ever.
Widths of circle here you see.
Sketched out in strange obscurity.

3.1415926535897932384626433832795 (Should we stop here?)

Should you have a repressed desire to experience a brain implosion, try these:
Near A Raven, an Edgar Allen Poe-esque poem which currently holds the record for longest pi mnemonic, at 740 digits.
Cadaeic Cadenza, a short story (!) which is longer still at 3835 decimal places, and has additional constraints.

You may faint now.

Find the Area and Circumference of a Circle.

Tweedle-dee-dum and Tweedle-dee-dee,
Around the circle is pi times d,
But if the area is declared,
Think of the formula π "r" squared.

"Around the circle" is the circumference.
Circumference = π × d (diameter).
Area = π × r(radius) squared.

Area Of A Circle (see area of circle)
Apple pie are square: A = π × r²
Apple pie are round: A = π × r × r

Circumference Of A Circle (see circumference of a circle)
Cherry pie delicious!: C = π × d

Isosceles Triangle (see isosceles triangle)

Sing this to the tune of "Oh Christmas Tree":
    Oh isosceles, oh isosceles
    Two angles have
    Equal degrees

    Oh isosceles, oh isosceles
    You look just like
    A Christmas tree

A sentence to help you spell isosceles
I sat on sunny cliff eating lovely egg sandwiches

(contributed by Margaret and her student)

Complementary angle
Complementary angles form 90 degrees
Complementary angles form a corner.

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