Tutor MathsGuru: Ask me for your burning Maths questions!

[Dharma]

Nebbermind:

Dharma:

[quote=\"maths6a\"]http://www.postimage.org/image.php?v=TsdpVqJ





In the figure, KE = EL, AE = ED and BC is 3 times KB. Area of rect ABCD is 94 cm2 and the area of triangle KGB is 6 cm2.
Find the area of triangle KEL.

Thx for the tips. With some trial and error finally got it up. Please let me know what you think of this question. Thanks. :?

http://www.postimage.org/image.php?v=PqLd5uS

if the base of half the larger triangle is 2.5 times that of the smaller triangle, then the area is 6.25 times.

6 x 6.25 = 37.5

Area of KEL = 2 x 37.5 = 75

Is there something wrong with the question or my calculation? :?

P.S.

If BC is 3 times KB, then rect ABCD will be 9 times the area of the rect formed by 2 nos. of KGB, ie, 9 x 12 = 108. Yah? But it seems like CL is unknown[/quote]Thanks for highlighting, Nebbermind.

Seems like there is a flaw in Qn. The area of rect ABCD should be 90cm2 instead of 94cm2. You're correct.


http://www.postimage.org/image.php?v=PqNP01i

[maths6a]

Is the answer 77 or 78 1/3? Which is more acceptable? Thanks....... :?:


Apparently answer from schoolS' teacherS is 77. THanks.
Oh when I use 77 to workbacks, base and height don't tally.
When I use 78 1/3, they are ok.

Who that clever person who knows to change 94 to 90?

That was what I have been told to do. But I just want to know what should the answer be if it's 94. thanks, very stubborn me.

[maths6a]

Oh another question, is it wrong to for example convert 4500m to km and write 4.500km? Is it mathematically wrong and will marks be deducted? Thanks.

[OngMum]

Hi Mathsguru,


I have two questions that need your gudiance:

1. The figure below is made up of 4 squares and a rectangle. Rectangle ABCD has a perimeter of 40cm. The total area of the 4 squares is 500cm2. Find the area of the rectangle.

http://www.postimage.org/image.php?v=gxKXsSS

2. The figure below, not drawn to scale, shows three triangles of differnet sizes overlapping one another. The sum of areas of Triangle A and Triangle C is 30% that of Triangle B. 12.5% of Triangle A is shaded, 5% of B is shaded and 20% of Triangle C is shaded. Express the area of Triangle A as a percentage of the area of Triangle C.

http://www.postimage.org/image.php?v=gxKY8hi

Thank you! Cheers!

[Almighty]

OngMum:

Hi Mathsguru,


I have two questions that need your gudiance:

1. The figure below is made up of 4 squares and a rectangle. Rectangle ABCD has a perimeter of 40cm. The total area of the 4 squares is 500cm2. Find the area of the rectangle.

http://www.postimage.org/image.php?v=gxKXsSS

2. The figure below, not drawn to scale, shows three triangles of differnet sizes overlapping one another. The sum of areas of Triangle A and Triangle C is 30% that of Triangle B. 12.5% of Triangle A is shaded, 5% of B is shaded and 20% of Triangle C is shaded. Express the area of Triangle A as a percentage of the area of Triangle C.

http://www.postimage.org/image.php?v=gxKY8hi

Thank you! Cheers!

Hi Ong mum,
Let me try,
1.Let the breadth of the rectangle be m
and its length be n
therefore, 2m + 2n = 40 \t\t\t\t
m + n = 20\t\t\t\t
given that the total area of squares = 500,ie., 2m2 + 2n2 = 500\t\t\t\t
m2 + n2 = 250 cm2\t\t\t\t
using trial n error, m = 15 and n = 5\t\t\t\t
therefore area of the rectangle = 15 X 5 = 75cm2

[Almighty]

[/quote]

No worries, Almighty. I’ll try my best to answer if time permits.

Good luck and study hard.[/quote]

HI Dharma Sir,

Thankyou for your wishes. Will give my best!!!

[Dharma]

OngMum:

Hi Mathsguru,


I have two questions that need your gudiance:

1. The figure below is made up of 4 squares and a rectangle. Rectangle ABCD has a perimeter of 40cm. The total area of the 4 squares is 500cm2. Find the area of the rectangle.

http://www.postimage.org/image.php?v=gxKXsSS

2. The figure below, not drawn to scale, shows three triangles of differnet sizes overlapping one another. The sum of areas of Triangle A and Triangle C is 30% that of Triangle B. 12.5% of Triangle A is shaded, 5% of B is shaded and 20% of Triangle C is shaded. Express the area of Triangle A as a percentage of the area of Triangle C.

http://www.postimage.org/image.php?v=gxKY8hi

Thank you! Cheers!

Q1)

http://www.postimage.org/image.php?v=PqQbZyr


Q2)

12.5% of A is shaded
20% of C is shaded
5% of B is shaded

100% of A + 100% of C = 30% of B -------------(1)
12.5% of A + 20% of C = 5% of B ------------------(2)

75% of A + 120% of C = 30% of B ………………..(3) = (2) X 6

100% of A + 100% of C = 75% of A + 120% of C
25% of A = 20% of C
A = 80% of C

[Dharma]

maths6a:

Is the answer 77 or 78 1/3? Which is more acceptable? Thanks....... :?:


Apparently answer from schoolS' teacherS is 77. THanks.
Oh when I use 77 to workbacks, base and height don't tally.
When I use 78 1/3, they are ok.

Who that clever person who knows to change 94 to 90?

That was what I have been told to do. But I just want to know what should the answer be if it's 94. thanks, very stubborn me.

Hi maths6a,

The area of rect ABCD cannot be 94cm2. See below

http://www.postimage.org/image.php?v=aVAo6QJ

[maths6a]

ok. Thanks for taking time to clarify.

[Dharma]

maths6a:

ok. Thanks for taking time to clarify.

No worries