MATH QUIZ for 10 June 04

[Ralph Jones]

Good Evening Friends,
A lady has just come to your shop and ordered 12 planters with 12 sides each.

What would be the length of the sides with a circumscribed diameter of 1 foot?

Also what degree of angle would you cut on the edges of the boards?

Respectfully, :)

[craigb]

Ralph,
As you know, you are posting on an Australian board. Just so you know, we don't say "math" we say "maths".
I'm not having a go at you, just pointing out another difference between English and American.

I have no idea what the answer is to your question. :o

Respectfully
Craig

[bitingmidge]

..and probably with our metric system, she'd be thinking of a 10 sided pot, which would have an angle of 144° but because we couldn't work out the length of the sides, (Hopeless at maths you see), she would have to take a size of " about that"!!

Over to someone else now....I hear my Mum calling.....


Cheers,

P

[Sturdee]

..and probably with our metric system, she'd be thinking of a 10 sided pot, which would have an angle of 144° but because we couldn't work out the length of the sides, (Hopeless at maths you see), she would have to take a size of " about that"!!


And if she does not like that she could go to Bunnies who have a large range in stock and if not they will order it in. :D Or sell her a few half barrells so you can first drink the wine then cut them in half. :D

Peter.

[Ian007]

but having first drunk the contents of the wine barrel you would not be in any fit state to go anywhere near a power tool for about year. and if you did the cut on the barrel would probably look like a dogs hind leg!

secondly whats wrong with a square planter box?

circumscribed sounds like its not 2 far removed from a Jewish tradition! :eek:

Cheers Ian

[Robert WA]

12 sides means 24 angles, one for each end of each board. 360/24 = 15 degrees off square for each end of each board.

Method #1. The circumference of a circle with diameter 1' is pi x diameter = the value of pi (3.14159265358979323846264) in feet. 12 arcs, so each arc is 3.14159265358979323846264/12 in feet or 3.14159265358979323846264". The straight line between the ends of an arc is less than the arc itself.There is a formula for calculating that length, but I don't remember it.

Method #2. You end up with 12 triangles each with 2 sides of 12 inches and the angle between those equal sides is 15 degrees. There is a method of calculating the length of the 3rd side, but I don't remember that either.

Take it from here, someone. PLEASE!!!!!

In a previous life I was a matrimonial lawyer. The only maths I needed to know was division by 2.

[Ralph Jones]

Hello Guys,
I am going to try to attach something that will help you out in figuring this quiz.

Hope it works, if not I will type it in when I answer the quiz.

Respectfully, :)

[Sturdee]

.
In a previous life I was a matrimonial lawyer. The only maths I needed to know was division by 2.

I thought it was by 3. One third to each of party and the remaining thirds was the lawyer's fee. :D

Peter.

[Tonz]

360/12 = 30 degrees per sector.

Internal angles of any triangle = 180 degrees. Triangle is symmetrical, therefore both other angles = 75 degrees. (30 +75 +75 = 180) This is the angle of cut.

Dia = 1' Radius = 0.5' = 6"

Split triangle in 2 to form two right angled triangles.

Simple trig rules for any right angle triangle as below. We know angle A = 75 degrees. Length c = 0.5'

COS 75 degrees = b / 0.5 Therefore b = COS 75 x 0.5 = 0.1294'

Length of side = 2 x b = 0.2588' = 3.1058" = approx 3 7/64"

[Ralph Jones]

Good Morning Friends,
Tonz, you are indeed correct in your answer of 3 7/16" per side with a 15 degree angle.

Fellows if you will look up to my other post you will find the polygon formula that I attached. just click onto it and enlarge it, then print it out for some great help to you in figuring these different things out.

Don't worry as it is a JPEG image and guaranteed virus free. Email me if you have any questions.

Thank you for your support.

Respectfully, :)