Remark
It is not a straight line distance from the park to the mall. None of the answers give you that result. And if you know what displacement is, none of the answers are really displacement either. The distance is sort of a "as the crow flies." distance. There's a stop off in the middle of town.
Method
You need to use the Pythagorean Formula twice -- once from the park to the city Center and once from the city center to the mall.
Distance from the Park to the city center.
a = 3 [distance east]
b = 4 [distance south]
c = ??
c^2 = 3^2 + 4^2 Take the square root of both sides.
c = sqrt(3^2 + 4^2)
c = sqrt(9 + 16) Add
c = sqrt(25)
c = 5
So the distance from the park to the city center is 5 miles
Distance from City center to the mall
a = 2 miles [distance east]
b = 2 miles [distance north]
c = ??
c^2 = a^2 + b^2 Substitute
c^2 = 2^2 + 2^2 Expand this.
c^2 = 4 + 4
c^2 = 8 Take the square root of both sides.
sqrt(c^2) = sqrt(8)
c = sqrt(8) This is the result
c = 2.8
Answer
Total distance = 5 + 2.8 = 7.8
