Tutor MathsGuru: Ask me for your burning Maths questions!

[acehkr3009]

atutor2001:

acehkr3009:

..


My solution to my son....I told him that the height can never be longer than slanted side which is 10cm. With this, use guess & check to do 6 (half of 12cm) x 9 or 8 or 7... until he gets one of the answer in the MCQ, which is 48 cm sq. I think that will be the simplest option in the context of Primary level.

Thanks all for trying..

I believe your approach is the same as what setter of the question has in mind. To find the area without knowledge of Pythagoras theorem is equivalent to the discovery of Pythagoras theorem. Was googling and found this site very interesting on how Pythagoras theorem can be proven.

http://www.1728.com/pytproof.htm

Thanks for the link...great visual in showing Pythagoras theorem instead just remembering the formula = More fun in understanding maths....

[iFruit]

atutor2001:

acehkr3009:

..


My solution to my son....I told him that the height can never be longer than slanted side which is 10cm. With this, use guess & check to do 6 (half of 12cm) x 9 or 8 or 7... until he gets one of the answer in the MCQ, which is 48 cm sq. I think that will be the simplest option in the context of Primary level.

Thanks all for trying..

I believe your approach is the same as what setter of the question has in mind. To find the area without knowledge of Pythagoras theorem is equivalent to the discovery of Pythagoras theorem. Was googling and found this site very interesting on how Pythagoras theorem can be proven.

http://www.1728.com/pytproof.htm

I'm not too sure about that. Surely the P4/P5s know decimals/fractions and that lengths need not be whole numbers, no?

IMHO, it is better not to teach this sort of heuristics as they might become a habit to the detriment of conceptual understanding.

I think the question was mistakenly set out of syllabus. It is probably best to introduce Pythagoras theorem at this point (they will love it) or just skip the problem.

Just my 2 cents (you can throw away )

[wkong]

Hi All,


Need help for the following:

Based on the diagram I have attached, what is the maximum amount of Figure A that can be cut out of the rectangle?


http://postimage.org/image/1eyvrals4/

[iFruit]

wkong:

Hi All,


Need help for the following:

Based on the diagram I have attached, what is the maximum amount of Figure A that can be cut out of the rectangle?


http://postimage.org/image/1eyvrals4/

If you join two of the triangles, it becomes a 4x3 cm rectangle.

Maximum number 4x3 rectangles that can fit in the big rectangle = (28/3) x (16/4) = 36 (3cm along length wise, 4cm along breadth wise)

So max triangles that can be cut out = 36x2 = 72.

PS: if you cut the other way, you will end up with 70.

[wkong]

Hi iFruit,


Thanks for getting the answer. My kid got the answer 72 too, but another classmate of his say is 74. So which one is correct? Confused. :?

[iFruit]

wkong:

Hi iFruit,


Thanks for getting the answer. My kid got the answer 72 too, but another classmate of his say is 74. So which one is correct? Confused. :?

Hi wkong,

I think 74 is arrived at by rounding off (area of rectangle / area of triangle) = (28x16/6). But it is wrong as you can't cut more than 72 triangles as the remaining area can't be cut into required triangles.

HTH

[wkong]

iFruit:

wkong:

Hi iFruit,


Thanks for getting the answer. My kid got the answer 72 too, but another classmate of his say is 74. So which one is correct? Confused. :?

Hi wkong,

I think 74 is arrived at by rounding off (area of rectangle / area of triangle) = (28x16/6). But it is wrong as you can't cut more than 72 triangles as the remaining area can't be cut into required triangles.

HTH

Thanks.

[snowball]

:? Dear All, please help to ans the following Pr 3 maths...


Miss Tan bought some balloons for her pupils. If she gave each of her pupils 6 balloons, she would have 2 balloons left over. If she gave each of them 8 balloons, she would be short of 2 balloons. What was the least possible number of pupils Ms Tan had ?

Thnks

[Muffins]

snowball:

:? Dear All, please help to ans the following Pr 3 maths...


Miss Tan bought some balloons for her pupils. If she gave each of her pupils 6 balloons, she would have 2 balloons left over. If she gave each of them 8 balloons, she would be short of 2 balloons. What was the least possible number of pupils Ms Tan had ?

Thnks

Make the number of units x.

So, 6x + 2 = 8x - 2

Adding back the negative 2, we get: 6x + 4 = 8x

8x - 6x = 4

2x = 4

x = 2

Cheers!

[thir-teen]

snowball:

:? Dear All, please help to ans the following Pr 3 maths...


Miss Tan bought some balloons for her pupils. If she gave each of her pupils 6 balloons, she would have 2 balloons left over. If she gave each of them 8 balloons, she would be short of 2 balloons. What was the least possible number of pupils Ms Tan had ?

Thnks

http://postimage.org/image/1ctdwm10k/