Math Is Fun Forum

kcleigh2

Member

Registered: 2005-11-24

Posts: 13

please please please help i am sooooo soooo sooooo bad at maths

hi please could somone help me im sure im maths dislecsic. please help my maths tutor has given me some questions to answer and i cant seem to get my head around it at all. it might be that im just lazy and that im not really interested in maths but you never know iv tried and tried and tried and i still get the wrong answers can someone please help me!!!
here are some of the questions

1) a bicycle wheel has a diameter of 55cm.

a) how far is it round the wheel (1 d.p)?
b)if the wheel turns 50 times, calculate how far the bicycle has travelled. TO THE NEAREST CM?
C)HOW MANY TIMES (to the nearest whole number) WOULD THE WHEEL TURN IN A CYCLE RIDE OF 250 METRES?

2) the accss nursing home has a circular pond in the grounds. the pond is 100 metres acreoss and is surrounded by a narrow concrete path.as part of his recovery program, arthur wants to walk at least 1200 metres each day. how many times (TO THE NEAREST WHOLE NUMBER) should he walk around the pond to ensure that he covers this distance?

3)one method of measuring an irregular path is to use an odometer. this is a wheel attached to the handle by means of which it can be pushed along the irregular path. also attached to the whell is a device which counts the number of times the wheel is turned. one odometer has a 30cm diameter wheel and when pushed along a path through some woods turned 417 times. calculate the length of the path to the nearest metre.

Please could you help me with these i have more but i dont want to bombard you all so ill just try and get the jist of these first thanks from mandy

Last edited by kcleigh2 (2006-01-23 11:24:49)

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i am really really really rubbish at maths lol lol lol lol lol lol lol lol lol lol lol lol

kempos

Member

Registered: 2006-01-07

Posts: 77

Re: please please please help i am sooooo soooo sooooo bad at maths

a. 55pi
b. 2750pi

irspow

Member

Registered: 2005-11-24

Posts: 1,055

Re: please please please help i am sooooo soooo sooooo bad at maths

1) You are given the diameter of the wheel,  D=55cm.  When they ask how far it is around the wheel, they are asking for the circumference of the wheel.

    The circumference of any circle is defined as:  C = 2πr or πD

    Where D = diameter and r = radius = D/2

    a) C = πD = 55π = 172.8cm

    b) Each time the tire turns a complete revolution it travels a distance equal to the                  circumference.

        d=distance
       
        d = C×revolutions = πDrevs = π55×50 = 8639.37 = 8639cm(rounded)

    c)  Similar to above;

        d = C×revolutions,  but this time were given the distance traveled.

        250m = 55cmπ×revs, but you must convert 250m into cm first!

        250m×100cm/1m= 25000cm

        revs = 25000/55π = 144.68 = 155(rounded)

2)   If Arthur walks around this pond on a sidewalk built around it he will cover no less than the circumference of the pond no matter where on the sidewalk he walks or how narrow it may or may not be.  Arthur wants to walk at least 1200m

      d <Crevs;

      revs > d/C;  revs > d/πD;  revs > 1200/100π = 3.819 = 4 laps(rounded)

3)  Same formula again.

     d = C(revs),

     d = πD(revs),

     d = 30cmπ(417) = 39301.3241cm,  but they wanted the answer in meters.

     39301.3241cm(1m/100cm) = 393.01m = 393m(rounded)

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I am at an age where I have forgotten more than I remember, but I still pretend to know it all.