Help with Essex 11+ Maths 2005 paper Question 26
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Help with Essex 11+ Maths 2005 paper Question 26
Can anyone help me solve this question please. A four side polygon has two diagonals. If a polygon has 9 diagonals how many sides does it have?
My husband and daughter both came up with 18 (I am rubbish at maths, so didn't even attempt it). According to the marking scheme the answer is 6.
I will be grateful for an axplanation as to how to calculate number of sides from diagonals given and vice versa.
Thank you
My husband and daughter both came up with 18 (I am rubbish at maths, so didn't even attempt it). According to the marking scheme the answer is 6.
I will be grateful for an axplanation as to how to calculate number of sides from diagonals given and vice versa.
Thank you
Re: Help with Essex 11+ Maths 2005 paper Question 26
I get children to draw this one out.
3 sides 0 diagonals
4 sides 2 diagonals
5 sides 5 diagonals
6 sides 9 diagonals
There is a formula but it is beyond most 11 year olds
n(n - 3)/2
n is the number of sides, so for a six sided shape we have
6(6 - 3)/2
6 x 3 / 2
18/2 = 9
3 sides 0 diagonals
4 sides 2 diagonals
5 sides 5 diagonals
6 sides 9 diagonals
There is a formula but it is beyond most 11 year olds
n(n - 3)/2
n is the number of sides, so for a six sided shape we have
6(6 - 3)/2
6 x 3 / 2
18/2 = 9
Re: Help with Essex 11+ Maths 2005 paper Question 26
Thanks moved ,I actually thought the question was moved ..lol
@OP just as moved mentioned I think this is one in which they will have to use their memory ,just like they normally do for lines of symmetry ..I've come across that kind of question several times and have never seen one that needed the algebraic formula to solve .It's more about testing their ability to solve simple word problems using knowledge they've acquired over the school years .
@OP just as moved mentioned I think this is one in which they will have to use their memory ,just like they normally do for lines of symmetry ..I've come across that kind of question several times and have never seen one that needed the algebraic formula to solve .It's more about testing their ability to solve simple word problems using knowledge they've acquired over the school years .
Re: Help with Essex 11+ Maths 2005 paper Question 26
See the explanation posted recently here: http://www.elevenplusexams.co.uk/forum/ ... 73#p322873
Re: Help with Essex 11+ Maths 2005 paper Question 26
Thank you very much, moved, peter doe and okanagan. I'll pass this on to my husband.