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primary 6 | Maths | Measurement
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Nancy woods
Nancy Woods

primary 6 chevron_right Maths chevron_right Measurement chevron_right Singapore

Anyone knows why part b is not 50? Correct answer is 48.

Date Posted: 3 years ago
Views: 494
Christmas MT
Christmas MT
3 years ago
When we divide length of cardboard (100cm) by length of triangle (24cm), we get 4.17, meaning in reality, only 4 columns of triangles can be cut out because the remaining length is not enough for us to cut out the triangle that we want.

When we divide breadth of cardboard (60cm) by breadth of triangle (10cm), we get 6, meaning in reality, 6 rows of triangles can be cut out.

So we have 6x4=24 rectangles with length and breadth of 24cm and 10cm.

To get triangles from the rectangle. we will cut diagonally, meaning to say split each rectangle into two.

So number of triangles will be 24x2=48.
Hope this helps.
sstrike
Sstrike
3 years ago
26 is redundant

See 3 Answers

You'll need to consider the dimensions of the paper (100cm by 60cm)
Every two triangles can be paired together to form a rectangle that is 10cm by 24cm.
You can cut the 10cm sides of the rectangles from the 60cm length of the paper.
Number of such rectangles that can be cut from this side = 60 cm ÷ 10 cm = 6
The 24cm sides can be cut from the 100cm breadth of the paper.
Number of such rectangles that can be cut from this side = 100cm ÷ 24cm = 4 R 4cm
So only 4 rectangles can be cut breadthwise. The remaining 4cm is not wide enough to cut more rectangles.
Total number of rectangles = 6 × 4 = 24
Since 2 triangles can be cut from each rectangle, total number of triangles = 24 × 2 = 48
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J
J's answer
1024 answers (A Helpful Person)
1st
J
J
3 years ago
If you do it the other way :

①Cut the 10cm sides from the 100cm length of the paper.
②Cut the 24cm sides from the 60cm breadth of the paper

Number of rectangles that can be cut lengthwise = 100cm ÷ 10cm = 10

Number of rectangles that can be cut breadthwise = 60cm ÷ 24cm = 2 R 12cm

Number of rectangles here = 10 × 2 = 20
Number of triangles here = 20 × 2 = 40

Now,

This 12cm space can fit more rectangles but they have to be oriented perpendicular (at right angles) to the other rectangles

Number of rectangles that fit this width = 1
(Since 12cm ÷ 10cm = 1 R 2cm)

Number of rectangles that fit along the 100cm length = 100cm ÷ 24cm = 4 R 4cm

Number of rectangles here = 4 × 1 = 4
Number of triangles here = 4 × 2 = 8


Total number of triangles = 40 + 8 = 48

It is still the same number, so the greatest number is still 48
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sstrike
Sstrike's answer
5567 answers (A Helpful Person)
similar
- divided into different parts
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sstrike
Sstrike's answer
5567 answers (A Helpful Person)