Multiply. check for reasonableness 77x3

Really need on these. i have no idea what to do

Could somebody me with this radical simplification?

5. which description does not guarantee that a quadrilateral is a squar ajo is a parallelogram with perpendicular diagonals 0% has all sides congruent and all angles congruent o has all right angles and has all sides congruent 10% is both a rectangle and a rhombus 30%