Since the shrub was 64 cm tall at first, take away 64 from 76.6. Now we are left with 12.6. Let's divide 12.6 by 1.8 (that's how many cm it grows per week). When we do this, we are left with 7. This means it took 7 weeks for the shrub to reach 76.6 cm. I hope this helps!
Step-by-step explanation:A rhombus is a quadrilateral with all sides equal in length. A square is a quadrilateral with all sides equal in length and all interior angles right angles. Thus a rhombus is not a square unless the angles are all right angles