On a map,a length of 4cm represents an actual distance of 8000m. Calculate
a)The scale of the map,in the form 1 : n
b) the actual distance,in km,represented by 18cm on the map.
c)the area on the map,in cm^2,given that the actual area is 4km^2.
part a) and b) can do,but c) cannot \:
Can help?
4cm: 8km
1cm: 2km
Area Scale
1cm2:4km2
So area on the map = 1cm2.
a 1 : 200000
b 36
1 cm : 200000 cm
1 cm^2 : (2km)^2
1cm^2 : 4 km^2
lol the answer for c is just 1 cm^2
1cm: 800000cm
1cm^2:(800000)cm^2
therefore 1cm^2:640000000000cm^2
640000000000cm^2 = 64km^2
1cm^2 = 64km^2
therefore 4km^2 = 1/16cm^2
that was rubbish. sry
4cm: 800000cm
1cm: 200000cm
1cm^2:(200000)cm^2
therefore 1cm^2:40000000000cm^2
40000000000cm^2 = 4km^2
1cm^2 = 4km^2
therefore 4km^2 = 1cm^2
Hey, for this kind of question, I would reccomend you to do it step by step, there's no hurry during the exams. (:
So, given that,
4cm : 8000m
=> 4 cm : 800 000 cm
For area, since the units are cm^2 and km^2 respectively, it means simply (cm * cm) and (km * km), just like a * a = a^2, with this understanding we'll change the units respectively to what the question requires:
4 cm : 8 km
If we square our units, we have to square our numbers as well, so we'll have:
4^2 cm^2 : 8^2 km^2
16 cm^2 : 64 km^2
By simple proportion,
64 km^2 -> 16 cm^2
4 km^2 -> 16/64 * 4
= 1 cm^2
(: I hope I don't make any mistakes, but it should be correct.
Small note. For cdalculation that has to do with area, change the units first before you square it. XD otherwise you wld have tons of 0s to deal with.
well done everyone
Ganbatte!!!!!
wah thanks everyone! :DD