Math - What is Pi - Challenge

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#21

Thank you! :wink:

In fact I noticed that my result was quite off when compared to fellow students, something like 50.24, so I ended up using τr value on calculator, too bad there is no tau function on the calculators I have installed on Windows and Android; result was 50.265 and I took the floor instead of rounding up, that’s why my answer is not correct.

By the way I’m just brushing up and reinforcing these topics, just a couple of years ago I spent quite some time on Khan academy following all the way to integral calculus so trigonometry is a no sweat for me; I have only have to review tangent, cotangent, secant and cosecant identities, but I’m not skipping any lectures.

#22

C = 2 TT R

C = 8 * TT * 2
C= 16 TT or 8T
C = 50.27 units

#23

C = 16π
C = 16 * 22/7
C = 2.285 * 22
C = 50.27

#24

50.27
8(2pi)
16(pi)

#25

The answer is = 2 * pi * 8 = 50.27

#26

C = 16 x 3.14159
C = 50.27

#27

Here we go!

C = 2πr
= 16π
= 50.27 (to 2 decimal places)

#28

circumference=2pir=2pi8=16pi is about 50.27

I’ll have to be convinced about the tau thing. Dealing with areas and volumes I’m not a big fan of having to account for extra divisors ala area = pi*r^2 = ((tau)/2)*r^2. Then again I also prefer 4 significant digits.

#29

its 16 pi or 50.27

#30

c = 2πr or c = τr
r = 8
c = 16π = 8τ = 50.27

I also learned:
windows key + period = symbols keyboard
on the top row go to Ω section
then on the bottom row go to Ω section
Untitled

#31

c = 2πr
r = 8
c = 16π

#32

Turret has a firing range of 8 units, and an unlimited rotation. What is the circumference of the circle drawn by this turret’s firing range?

C = τ8

or π * 16 = 50.265482

#33

C = τr
C = 8τ

#34

Find circumference with a radius of 8 when using Pi as 3.14.

(c/2(8)) = π
(c/16) = π
c = 16π
c = ≈50.24

Testing:
(50.24/π)/2 = r
16/2 = r
8 = r

Answer: c = ≈50.24 (units?)

#35

Here’s my answer for the What is PI challenge:

Q1. Given a radius of 8, what is the circumference?

A1. ~50.27 (or 16π, or 8τ)
A1a. c = 2πr
A1b. c = 2π8
A1c. c = 16π or ~50.27

Tau alternative:
A1d. c = τr
A1e. c = 8τ

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#36

This really is a good reminder to be careful about your rounding.

I got exactly 50.24 when I rounded pi before calculating (i.e., multiplied 8 * 2 * 3.14), versus 50.27 (rounded up from 50.265482457436691815402294132472) when I multiplied pi * 2 * 8 using a scientific calculator.

Not a massive difference, but I’d wager it could cause some “unintended features” in one’s code.

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#37

2 x 𝝅 x 8 = 50.26
rounded two decimal places.

#38

Thank You so much for the YouTube link to the “Tau vs Pi Smackdown - Numberphile”. Big fun to watch :smile:

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#39

d = 2r = 16
c = dπ
c = 16π
c = 50.267

1 Like
#40

50.24

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