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In another Battleships qaxwQ, Rosa marked the hits and
misses on Nathan's ships as shown below. A hit is shown
by shading in the block. A miss is shown by drawing a
X
cross. A line is drawn through the blocks when a ship is
X X X X
sunk.
X X X
O Which one of Nathan's fleet has Rosa already sunk?
X X X X X
O Which squares around this sunk vessel can Rosa cross X X
out knowing that no ships are on these squares? How
X
does she know?
@ What type of ship might Nathan have at G10?

O Part of the cruiser is on G3. Give the grid references
for further hits on the cruiser.
X X
O If the hit at A2 was on an aircraft carrier, give the A B C D E F G H
possible grid references of the other hits on it. Nathan's Ships

11.1.2 Plotting coordinates

After recalling how to use a grid reference, let us now look at coordinate grids.
A grid reference gives the position of a square, but a coordinate point can give a
more specific position on a grid.

Coordinates are an ordered pair of numbers. They give the position of a point on
a set of axes. Look at the coordinate grid below.

We call this line the
y-axis. The numbers
on this line are
The arrows on the .v-axis
y-coordinates.
and the yaxis show that
secon 1 irst
the lines go on and do not qu idra It quadrant
stop. The point .We call this line
where the
the x-axis. The
A-axis and numbers on
2nd 1st y-axls meet 5 - 4 - 3 - 2 -1 0 5 . X
} this line are the
3rd 4th is called the x-coordinates.
origin. 7
1 Tird t. urti 1
qu^drant ■3, qu nt

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2461 UNIT 11 I Coordinate Geometry and Graphs