Please help me please

Arectangle has a length of 6cm by 8cm what is the length of a diagonal of the rectangle

Amass weighing 16 pounds stretches a spring 8/3 feet. the mass is initially released from rest from a point 2 feet below the equilibrium position, and the subsequent motion takes place in a medium that offers a damping force that is numerically equal to 1/2 the instantaneous velocity. find the equation of motion if the mass is driven by an external force equal to f(t)=cos(2t).

Hannah has 5 more than twice the number of baseball cards that leo has. if leo has x cards, which expression shows the number of baseball cards hannah has?