3rd grade math!

which of the following are characteristics that a rectangle must have?

i. opposite sides have the same length
ii. all sides have the same length
iii. all angles have different sizes
iv. all angles are the same size

15 point ! ~ see if you know the answer to both you!

If x is 6, then 7x= a. 13 b. 42 c. 42x d. 76

Adecorative window is made up of a rectangle with semicircles at either end. the ratio of ad to ab is 3: 2 and ab is 30 inches. what is the ratio of the area of the rectangle to the combined area of the semicircles? possible answers: a. 2: 3 b. 3: 2 c. 6: π d. 9: π e. 30: π