Prove that the given quadrilateral is a square. Show all the work

If a quadrilateral has four congruent sides and four right angles, then it's a square (reverse of the square definition). If two consecutive sides of a rectangle are congruent, then it's a square (neither the reverse of the definition nor the converse of a property)

Step-by-step explanation:

Sorry, If I'm wrong!  

f(x) has value 150 at x= 0

and 0 at x= 3

so d(f(x))/dt = slope = -150/3 = -50