Secondary 2 Mathematics..?

Q1. The map of Jurong Bird Park has a scale of 1 : 3000.
(a) If the length from the entrance to Flamingo Gardens is 4.5cm on the map, calculate the actual distance, in km.
(b) The actual area of the Parrot Enclosure is 0.0225km^2.
Calculate the area on the map that represents the enclosure, giving your answer in square centimeters.

Q2. A nature reserve of area 225km^2 is represented on a map by an area of 36cm^2. Find the R.F. of the map. What will be the area of the nature reserve be on another map whose scale is 1cm to 5km.

Q3.On a map, a road 4.8km long measures 12cm. Find
(a) the scale used in the form of R.F.
(b) the actual area of a field which measures 28cm^2 on the map.
(c) the area, in cm^2, of the same field on a second map whose scale is 1:20000.

Thanks in advance..
Test came out and got this 3 wrong..we're suppose to do our own corrections. But I still don't get what my teacher is saying. So please help..
With ur steps,, try to explain why too.. thanks..






Answer :
Q1. The scale is 1:3000 means 1cm is 3000 cm ,i.e., 1cm is 30 m

a) 4.5 cm on map means (4.5 * 30) m actually, now 4.5 * 30 = 225 m = 0.225 km
Hence answer should be 0.225 km

b) 0.0225km^2 means it should be a square region with length 0.15 km ,i.e., 150m, so according to the scale the length of the enclosure on the map should be 5cm.
Hence the area on the map will be 25cm^2.

Q2. 225km^2 means a square with the length as 15km and 36cm^2 means a square with the length 6cm. Hence the scale is 6cm is 15km, so 1cm is 2.5km means 1:250000.
On another map 1cm is 5km, so 15km will be 3cm. Hence the area of the nature reserve on another map will be 9cm^2.

Q3. 4.8km is 12cm, hence scale is 1cm is 0.4km or 400 m
(a) 1cm is 400 m so 1:40000
(b) 1cm is 400 m, so 1cm^2 will be 160000m^2 or 0.16km^2
So 28cm^2 is 28 * 0.16 = 4.48 km^2.
(c) 1:20000 means 1 cm is 0.2 km so 1cm^2 is 0.04km^2.
hence on another map the area will be 4.48/0.04 = 112cm^2