The distance between Mary and Rogers houses is 2.47 miles.
Explanation:
From the given information we can form a right angle triangle.
Refer to the image given below.
N mentions the north and W mentions the south.
S denoted the School.
M denotes Mary's home - 2.1 miles away from School and forms one side of the triangle.
R denotes Roger's home - 1.3 miles away from School and forms another side of the triangle.
The distance between their houses will be the hypotenuse side of the triangle.
Hypotenuse side =
.
=
.
=
.
=
.
= 2.47.
Distance between their houses =2.47 miles.