Answer:
The scale Myra should use is one graph unit = 400 km or;
←--→ = 400 km
Step-by-step explanation:
The question relates to the representation of scale drawing
The actual distance between Perth and Sydney = 3294 kilometers
The given coordinates of Perth on the grid = (1.3, 3.4)
The given coordinates of Sydney on the grid = (9.2, 3.3)
The measure of the distance between Perth and Sydney, 'd', is given by using the following formula for finding the distance between two points given their 'x', and 'y' coordinates;
[tex]d = \sqrt{\left (x_{2}-x_{1} \right )^{2}+\left (y_{2}-y_{1} \right )^{2}}[/tex]
Therefore, by substitution, we have;
[tex]d = \sqrt{\left (9.2-1.3 \right )^{2}+\left (3.3-3.4 \right )^{2}} = \sqrt{\left (7.9 \right )^{2}+\left (-0.1 \right )^{2}} = \dfrac{\sqrt{6242} }{10} \approx 7.9[/tex]
d ≈ 7.9 units
Therefore, we have;
7.9 units of the graph = 3294 kilometers
1 unit of the graph ≈ 3294/7.9 km = 416.962025316 km ≈ 416.96 km
Therefore, the scale Myra should use for her map is 1 unit = 400 km.