Answer:
Johnny and Sally essentially form a right-angled triangle with their paths. Johnny's eastward and northward movements create the legs of the triangle, while Sally's westward and northward movements form the other leg.
Using the Pythagorean theorem:
\[ \text{Hypotenuse}^2 = \text{Leg}_1^2 + \text{Leg}_2^2 \]
For Johnny:
\[ \text{Hypotenuse}_J^2 = 80^2 + 90^2 \]
For Sally:
\[ \text{Hypotenuse}_S^2 = 40^2 + 40^2 \]
Now, to find the distance between Johnny's apartment and Sally's house:
\[ \text{Distance} = \sqrt{(\text{Hypotenuse}_J)^2 + (\text{Hypotenuse}_S)^2} \]
Calculate this to determine the distance between Sally's house and Johnny's apartment.
