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#1 2007-03-15 04:08:28

soha
Real Member
Registered: 2006-07-07
Posts: 2,530

perfect squares

Show that each of the following numbers is a perfect square.Also,find the number  whose product is thenew number:-

a)1156
b)4761

please help me in both of the above problems urgently.
thanks


"Let us realize that: the privilege to work is a gift, the power to work is a blessing, the love of work is success!" smile smile
- David O. McKay

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#2 2007-03-15 04:31:25

JaneFairfax
Member
Registered: 2007-02-23
Posts: 6,868

Re: perfect squares

I take it you’re not allowed to use a calculator?

Well, one way you can do it with “working” is to recognize that 35² = 1225 and 70² = 4900. Then

(i) 34² = (35 − 1)² = 35² − 2·35 + 1² = 1225 − 70 + 1 = 1156

(ii) 69² = (70 − 1)² = 70² − 2·70 + 1² = 4900 − 140 + 1 = 4761

Alternatively, if you are not familiar with 35² = 1225, you should know that 30² = 900; then use 34² = (30 + 4)² as above.

Last edited by JaneFairfax (2007-03-15 04:34:11)

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#3 2007-03-15 04:39:00

soha
Real Member
Registered: 2006-07-07
Posts: 2,530

Re: perfect squares

just dont get it.
method used in one book is by taking LCM
can u please do this by that method


"Let us realize that: the privilege to work is a gift, the power to work is a blessing, the love of work is success!" smile smile
- David O. McKay

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#4 2007-03-15 05:17:17

JaneFairfax
Member
Registered: 2007-02-23
Posts: 6,868

Re: perfect squares

Sorry, I missed the second part of the question.

It’s not very clearly worded. Could you rephrase the second part of the question? neutral

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#5 2007-03-15 06:23:00

soha
Real Member
Registered: 2006-07-07
Posts: 2,530

Re: perfect squares

soha wrote:

Show that each of the following numbers is a perfect square.Also,find the number  whose product is thenew number:-

a)1156
b)4761

please help me in both of the above problems urgently.
thanks

sorry,
the second part of the question is:-
also,find the number whose square  is the   given number in each case
please do the first part again in prime factoritazion
or LCM method
please

thank u


"Let us realize that: the privilege to work is a gift, the power to work is a blessing, the love of work is success!" smile smile
- David O. McKay

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#6 2007-03-15 06:28:06

pi man
Member
Registered: 2006-07-06
Posts: 251

Re: perfect squares

I don't see how least common multiple applies here but factorization would help. 

1156 = 2 * 2 * 17 * 17 =  (2*17) * (2* 17) = (2*17)^2 = 34^2

4761 = 3 * 3 * 23 * 23 = (3*23) * (3*23) = (3*23)^2 = 69^2

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#7 2007-03-15 06:34:00

soha
Real Member
Registered: 2006-07-07
Posts: 2,530

Re: perfect squares

Thank U A Lot..


"Let us realize that: the privilege to work is a gift, the power to work is a blessing, the love of work is success!" smile smile
- David O. McKay

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