## Q&A - P5 Math

- AdaptiveLearning.sg
- YellowBelt
**Posts:**25**Joined:**Mon Jun 02,

### Re: Q&A - P5 Math

Height of small trianglettlkbs wrote:Another question on area, pls help :

= 1/2 x height of square (since P is the mid point)

= 1/2 x 15

Area of small triangle

= 1/2 x base x height obtained above

= 1/2 x 15 x 7.5

Area of bigger triangle

= 1/2 x base x height of square

= 1/2 x 15 x 15

Shaded Area

= Area of bigger triangle - Area of smaller triangle

- AdaptiveLearning.sg
- YellowBelt
**Posts:**25**Joined:**Mon Jun 02,

### Re: Q&A - P5 Math

Not sure if my calculations are off, but I can't get a consistent answer for this one.ttlkbs wrote:3rd and last question on area for this holiday!

Help pls :

Assuming the mid-point of BC is P.

The shortest calculation should be:

(i)

Area of triangle KEL

= Area of Rectangle formed by points K, P, E

= Area of ABCD / BP x KP

= 94 / 3 x 2.5

(ii)

However, using the similar triangles...

Area of triangle KEP

= Area of triangle KGB x (KP/KB)^2

= 6 x (2.5/1)^2

Area of triangle KEL

= 2 x Area above

The two yield different answers.

### Re: Q&A - P5 Math

It's so simple! Why couldn't I think of it?AdaptiveLearning.sg wrote:Height of small trianglettlkbs wrote:Another question on area, pls help :

= 1/2 x height of square (since P is the mid point)

= 1/2 x 15

Area of small triangle

= 1/2 x base x height obtained above

= 1/2 x 15 x 7.5

Area of bigger triangle

= 1/2 x base x height of square

= 1/2 x 15 x 15

Shaded Area

= Area of bigger triangle - Area of smaller triangle

### Re: Q&A - P5 Math

Maths Tutor Mr Lim, would you like to share how did you derive at 77 ?Maths Tutor Mr. Lim wrote:77AdaptiveLearning.sg wrote:Not sure if my calculations are off, but I can't get a consistent answer for this one.ttlkbs wrote:3rd and last question on area for this holiday!

Help pls :

Assuming the mid-point of BC is P.

The shortest calculation should be:

(i)

Area of triangle KEL

= Area of Rectangle formed by points K, P, E

= Area of ABCD / BP x KP

= 94 / 3 x 2.5

(ii)

However, using the similar triangles...

Area of triangle KEP

= Area of triangle KGB x (KP/KB)^2

= 6 x (2.5/1)^2

Area of triangle KEL

= 2 x Area above

The two yield different answers.

- MathIzzzFun
- KiasuGrandMaster
**Posts:**2358**Joined:**Wed Mar 09,**Total Likes:**5

### Re: Q&A - P5 Math

DIscussed @pg 335 --> http://tinyurl.com/ksp-P5maths-pg335AdaptiveLearning.sg wrote:Not sure if my calculations are off, but I can't get a consistent answer for this one.ttlkbs wrote:3rd and last question on area for this holiday!

Help pls :

Assuming the mid-point of BC is P.

The shortest calculation should be:

(i)

Area of triangle KEL

= Area of Rectangle formed by points K, P, E

= Area of ABCD / BP x KP

= 94 / 3 x 2.5

(ii)

However, using the similar triangles...

Area of triangle KEP

= Area of triangle KGB x (KP/KB)^2

= 6 x (2.5/1)^2

Area of triangle KEL

= 2 x Area above

The two yield different answers.

cheers.

### Re: Q&A - P5 Math

Please help anyone? Thanks in advance

**A store sells pens in packs of 2s (small) and 4s (big).**

At first there were 3 times more small packs than big packs.

After selling half of the small packs and some big packs, the shopkeeper packs

additional 5 big packs of pens. How many big packs are sold if there are thrice as many small packs as big packs and there is total 300 unsold pens?

At first there were 3 times more small packs than big packs.

After selling half of the small packs and some big packs, the shopkeeper packs

additional 5 big packs of pens. How many big packs are sold if there are thrice as many small packs as big packs and there is total 300 unsold pens?

### Re: Q&A - P5 Math

Thanks to all who have offered solutions.MathIzzzFun wrote:DIscussed @pg 335 --> http://tinyurl.com/ksp-P5maths-pg335AdaptiveLearning.sg wrote:ttlkbs wrote:3rd and last question on area for this holiday!

Help pls :

Assuming the mid-point of BC is P.

The shortest calculation should be:

(i)

Area of triangle KEL

= Area of Rectangle formed by points K, P, E

= Area of ABCD / BP x KP

= 94 / 3 x 2.5

(ii)

However, using the similar triangles...

Area of triangle KEP

= Area of triangle KGB x (KP/KB)^2

= 6 x (2.5/1)^2

Area of triangle KEL

= 2 x Area above

The two yield different answers.

cheers.

- geniuskids
- YellowBelt
**Posts:**25**Joined:**Mon Jul 05,

### Re: Q&A - P5 Math

Need help on this question:

Islani had to read a book for his school project. On the 1st day, he read 72 pages of the book. On the 2nd day, he read 1/4 of the remaining number of pages. In the end, he still had to read 1/2 of the total number of pages to complete the book. How many pages were there in the book?

Thank you.

Islani had to read a book for his school project. On the 1st day, he read 72 pages of the book. On the 2nd day, he read 1/4 of the remaining number of pages. In the end, he still had to read 1/2 of the total number of pages to complete the book. How many pages were there in the book?

Thank you.