[INST] On a Cartesian coordinate plane, points (2,1) and (3, 4) are adjacent points on a square. What is the area of the square?/n [/INST]  ###Response: We can use the distance formula to find the length of the square's side, which is the distance between the two points (2,1) and (3,4) on the coordinate plane. 

The distance formula is: 
distance = sqrt((x2 - x1)^2 + (y2 - y1)^2)

Plugging in the values from the given points, we get: 

distance = sqrt((3 - 2)^2 + (4 - 1)^2)
distance = sqrt(1 + 9)
distance = sqrt(10)

So the length of the square's side is sqrt(10). 

To find the area of the square, we can square the length of the side: 

area = (sqrt(10))^2
area = 10 

Therefore, the area of the square is 10 square units.