Question 328705
the boat is 8 km north and 15 km west of its starting point.


Let its starting point = the origin of a graph.


This means that x = 0 and y = 0.


Let west be the horizontal line along the x-axis and let y = the vertical line along the y-axis.


15 km west of its starting point would be at x = 15.


8 km north of its starting point would be at y = 8


The point on the graph where the boat is located is (x,y) = (15,8).


the distance of the boat from its starting point is the hypotenuse of the right triangle formed by a horizontal line of 15 km in length and a vertical line of 8 km in length.


the length of this line is equal to the square root of 15^2 + 8^2 which makes it equal to the square root of 225 + 64 which makes it equal to the square root of 289 which makes it equal to 17 km.


a rough sketch of the graph is shown below:


<pre>
                                 x
                               (0,8)                        (15,8)
                                 x                         x   x  
                                 x                     x       x  
                                 x                  x          x  
                                 x               x             x  
                                 x           x                 x  
                                 x       x                     x  
                                 x   x                         x  
 x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x 
                               (0,0)                        (15,0)
                                 x
                                 x
                                 x
                                 x
                                 x
                                 x

coordinates are expressed as (x,y)
x is the value of the x-coordinate
y is the value of the y-coordinate

</pre>