Help me with some math questions.. TOTALLY important grade 9 math questions?

1. A map is drawn using a scale of 4 cm to represent 5 km


a) find the representative fraction


b) A road has a length of 9.4 cm on the map, find its actual distance in km


c) A lake has an area of 64 km*2 find its area represented on the map





2. a cylindrical container of radius 8 cm contains water to a height of 5 cm. Th water in this cylinder is then poured into another cylinder of radius 5 cm. what is the height of the water in the second cylinder?





3. the length and breadth of a rectangle are (2x+1)cm and (x-1)cm respectively. If the area of the rectangle is 90cm*2, form an equation in x and hence calculate the value of x.





just the answers will do,thanks so much you'll really help this is totally important

Help me with some math questions.. TOTALLY important grade 9 math questions?
"Just the answers will do"???????????????





Please do your own homework. If you don't know how to do it- asking for help with that would be more appropriate.
Reply:1.a.the representative fraction is :


1:1.25(i.e.,1cm=5/4km)


b.1 cm on the map is 1.25km


therefore, 9.4cm on the map is


9.4*1.25=11.75km


c.64km^2=%26gt;a square of sides 8 km each


8 km in the map will be


0.8*8=6.4 cm.


therefore a square with sides 6.4 cm is to be drawn


2. the volume in the first cylinder is equal to the volume in the


second cylinder.


pi*8*8*5=pi*5*5*h


320=25h


h=12.8cm


3.(2x+1)(x-1)=90


2x^2-x-91=0


x=7,(-26/4)
Reply:1 a) 4cm/5km=4cm/500000cm=1/125000 it is unitless


b) 9.4x125000cm or 9.4x1.25km=11.75km


c) 64=8x8/1.25x1.25=7.04cm*2


2.V1=pie X r*2 X h =3.14x64x5=1004.8cum


hence 1004.8=pie X r'*2 Xh


1004.8=3.14x25xh


h=1004.8/3.14x25


=100480/7850


=12.8cm


3. A= (2x+1)(x-1)=90


=2x*2-x-91=0


x=7

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