Answer:
distance formula; definition of congruence ; if two consecutive sides of a rectangle are congruent, then it's a square
Explanation:
Given that RSTU is a rectangle with vertices;
[tex]\begin{gathered} R(0,0),S(0,a),T(a,a)\text{ and U(a,0)} \\ a\ne0 \end{gathered}[/tex]
So, using the distance formula;
[tex]RS=a\text{ units}[/tex]
Reason; distance formula
[tex]ST=a\text{ units}[/tex]
Since both side RS and ST have the same length, then;
[tex]RS\cong ST[/tex]
Reason: definition of congruence
So, since two consecutive sides of a rectangle are congruent then;
[tex]\text{RSTU is a Square}[/tex]
Reason: if two consecutive sides of a rectangle are congruent, then it's a square
