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secondary 4 | E Maths
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Elena
Elena

secondary 4 chevron_right E Maths chevron_right Singapore

I dun know how to do part (a) and (b). Pls provide step by step workings and solutions. And write clearly thanks

Date Posted: 4 years ago
Views: 210
Eric Nicholas K
Eric Nicholas K
4 years ago
Length scale is 1 : 250000

This means that 1 cm on the map translates to an actual length of 250000 cm or 2500 m or 2.5 km.

We can only use the length scale for direct comparison of 1-dimensional measurements such as lengths, diameters, circumferences, heights etc.

(Part a)

This is a direct comparison of lengths (1-dimensional comparison) so we can use the above length scale of 1 cm : 2.5 km.

Length of road of map
= 5.5 km * (1 cm / 2.5 km)
= 2.2 cm

(Part b)

This is a direct comparison of areas (2-dimensional comparison) so we CANNOT use the length scale directly. We must first convert the length scale into an area scale by squaring each side of the length scale.

Length scale is 1 cm : 2.5 km
Area scale is (1 cm)^2 : (2.5 km)^2
Area scale is 1 cm^2 : 6.25 km^2

Taking squares from the large number 1 : 250000 to become 1^2 : 250000^2 is not advisable as the number gets really large.

Now we can use this area scale of 1 cm^2 : 6.25 km^2 to make direct area comparisons.

Actual area of school
= 3.75 cm^2 * (6.25 km^2 / 1 cm^2)
= 23.4375 km^2

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Chong Xin Wei
Chong Xin Wei's answer
3 answers (Tutor Details)
1st
hope its correct and helps u
J
J
4 years ago
b) is correct.

a) the question is asking for the length on the map so got to divide by 250000