Maths again....help me pls?

Question

A map of a town is drawn to a scale of 1 : 20 000

A school has an area of 30 000 m^2.
Find the area of this school on the map.

Answer 1

A scale of 1:20000 refers to lengths.
So areas are scaled by 1:20000^2
= 1:400,000,000

So the area on the map will be
30,000/400,000,000 m^2
= 3/40000 m^2
= 3/4 cm^2
or 7.5 mm^2

Answer 2

1: 20,000 means 1 metre represents 20,000 metres.

1 sq. metre will represent 20,000 x 20, 000 = 400000000 sq. metres.

Area of the school is 30,000 sq.mtrs.

Area represented on the map = 30,000 / 400000000

= 3/40000 sq.mtrs.

If we take 1mm on the map, that would represent 20 metres.

1 sq.mm will represent 400 sq.mts

30000 sq.mtrs is represented by 30000/400 = 75 sq.mm

which is same as the first result but easier to visaulise. For example, 10 mm by 7.5 mm will be 75 sq.mm

Answer 3

Sweetheart, these are the basics you are learning right now. You need to learn to do it for yourself.

Getting through your homework and being able to go out is all well and good. But none of it matters when you come to the exams and realise you can't do it.

Figure it out for yourself and you'll be so much more pleased with yourself.