math.f.1

1.
(a)3.2cm = 3.2*3
= 9.6km
(b)900m = 0.9km
0.9/3 = 0.3cm

2.Find the R.F. of a map if the scale of the map is
(a) 3cm:24m
1cm = 8m
1 : 800
(b)1.5cm:4.5km
1cm = 3km
1 : 300000

3.
1cm=10mm
100 cm = 1000mm = 1m
1m = 100cm

4.
1000m= 1km
1m = 0.001km

5.
1000g=1kg
k = 10^3 = 1000

我覺得數學要多 d 做..要搞清楚 d concept, 唔明就問多幾次, 唔好靠死記
千祈唔好怕麻煩就逃避, exercise 做多 d, 諗多 d
你而家先 F.2, 絕對有得追啦~

1.A map is drawn to a scale of 1cm:3km.
(a)What is the actual distance represented by 3.2cm?
1cm:3km
so, 3.2 * 3 = 9.6 km
The actual distance is 9.6 km

(b)What length on the map represents 900m?
first, find the same unit of the scale.
1cm:3km = 1cm:3,000m = 1cm:300,000cm
900m=90,000cm
1:300,000 = x:90,000 (use scale to find the answer)
x=0.3cm


2.Find the R.F. of a map if the scale of the map is
(a) 3cm:24m
3cm:24m = 3cm:2400cm
find the same unit and divide 3 in both sides, so the answer is
= 1:800

(b)1.5cm:4.5km
1.5cm:4.5km = 1.5cm:4500m = 1.5cm:450000cm
find the same unit and divide 1.5 in both sides, so the answer is
= 1:300000


3.1cm=10mm
1m=100cm

4.1m=0.001km (1km=1000m)

5. 1000g=1kg

2007-07-23 00:12:51 補充：
There are just four words can include my opinion.It's practices and thinking more.

1a)3.2x3=9.6km
1b)0.3cm
2)咩係RF?
3)1m=100cm
4)1m=0.001km
5)1000g=1kg

3.1cm=10mm
1m=100cm

4.1m=0.001km

5. 100g=1kg

第2題我唔係好肯定
2.Find the R.F. of a map if the scale of the map is
(a) 1cm:8m
(b)1cm:3km