PLEASE HELPPP

Imagine a new pasture with grass growing on it. every day after the seeds have germinated, the number of blades of grass in the pasture triples. after 18 days, the entire pasture is completely covered in grass. how many days did it take for the pasture to be one-third covered in grass?

You can find the constant of proportionality by finding the ratio of

Me complete this proof! prove that a quadrilateral is a square. me with the steps for this proof.