Answer:
7.81 miles
Step-by-step explanation:
Assume Eastern and Southern displacement as positive and Northern and Western displacement as negative, the explorer's East-West and South-North displacements were:
[tex]E=4+3-2=5\ miles\\S=7-1=6\ miles[/tex]
His distance from his original position is:
[tex]D^2 = E^2+S^2\\D=\sqrt{5^2+6^2}\\ D= 7.81\ miles[/tex]