Prove a quadrilateral with vertices g(1,-1), h(5,1), i(4,3), j(0,1) is a rectangle

parallelogram method:
rectangle method:

i need understanding how to prove it's a rectangle

In the field of thermodynamics, rankine is the unit used to measure temperature. one can convert temperature from celsius into rankine using the formula , what is the temperature in celsius corresponding to r degrees rankine? a. 9/5(c - 273) b. 9/5(c + 273) c. 5/9( c - 273) d. 5/9( c + 273)