4. "The quadrilateral is regular" does NOT guarantee that a quadrilateral is a square.
Step-by-step explanation:
The first three descriptions give us a square.
The last one is not necessarily a square. It could be a trapezoid or kite and doesn't guarantee a square.
An acute angle measures less than 90 degrees, so the statement is true because the angle measures 43 degrees.
Its inverse statement is if an angle do not measure 43 degrees, then the angle is not acute. The answer is false because the angle can also be right, obtuse, and straight.
Therefore, the statement is true but the inverse is false.