Can someone please help I have a really important test soon I’ll give 100 points just plz help

I only understand 1

1.  10.3923

Step-by-step explanation:

Formula to find b = Plug in a = 6 and c = 12Next you do which is 144 and you also do which is 36. Plug in 144 to and plug in 36 to Subtract 144-36 to get 108Plug 108 to After you plug 108 in the equation you square root getting 10.3923.

yes it is.

diagonals of parallelogram bisect each other so if the diagonals are of equal length then they bisect each other and length of each bisect is equal. so the angle made by these bisects with any sides should be equal ( it is a theorem of geometry ) if all such angles are equal then the length all the sides with which these angles are made should of equal.now if all the sides has same length then it is rhombus and here all angles have same values that is x+x+x+x=360; x=90

so it is proved that it is a rectangle.