Help plz... what are the missing proof
A. Substitution; converse of diagonals theorem
B. Sum of interior angles; converse of opposite angles theorem
C. Substitution, converse of opposite angles theorem
D. Sum of interior angles; converse of diagonals theorem
I think it's between B and C ​

B. Sum of interior angles; converse of opposite angles theorem

Step-by-step explanation:

In statement 1, all the interior angles of the quadrilateral are added to give a sum of 360°. The reason would therefore be "sum of interior angles".

As a follow up to the already established fact that the opposite angles of the quadrilateral are congruent to each other, this satisfies the Converse of Opposite Angles Theorem, which states that if the opposite angles of a quadrilateral are congruent to each other then the quadrilateral must be a parallelogram.

Reason for the statement in number 6 is definitely "converse of opposite angles theorem."

see below

Step-by-step explanation:

f(x) = −16x^2 + 24x + 16

Set equal to zero to find the x intercepts

0  = −16x^2 + 24x + 16

Factor out -8

0 = -8(2x^2 -3x-2)

Factor

0 = -8(2x +1) (x-2)

Using the zero product property

2x+1 =0    x-2 =0

x = -1/2      x=2

The x intercepts are -1/2   ,2

Since the coefficient of x^2 is negative the graph will open down and the vertex will be a maximum

The x value of the maximum is 1/2 way between the zeros

(-1/2+2) /2 = 1.5/2 =.75

To find the y value substitute into the function

f(.75) = -8(2x +1) (x-2)

        =-8(2*.75+1) (.75-2)

        = -8(2.5)(-1.25)

         =25

The vertex is at (.75, 25)

We have the zeros, and  the vertex.  We know the graph is symmetrical about the vertex