Answer:
25
Step-by-step explanation:
The median of a trapezoid equals one half of the sum of the bases
AC is a median and EB and DF are the bases.
hence AC = 1/2(EB + DF) 
We are given that EB = 13 and that AC = 19. And we need to find DF 
To do so we plug in what we are given and solve for DF
AC = 1/2(EB + DF) 
AC = 19, EB = 13
19 = 1/2(13 + DF)
Now solve for DF 
* Multiply both sides by 2* 
19 * 2 = 38
1/2(13 + DF) * 2 ( the 1/2 and 2 cancel out and we're left with 13 + DF ) 
We then have 38 = 13 + DF
* Subtract 13 from both sides *
38 - 13 = 13 - 13 + DF
We get that DF = 25 
 
        
             
        
        
        
Well, there are two solutions.
Add both sides by 15.75 then from here, you can use quadratic formula.
So your answer should be x = -2.44949 or 2.44949.
        
             
        
        
        
Answer:
Option E
Step-by-step explanation:
The standard equation of circle is:- (x-h)² + (y-k)² = r²
where (h,k) is center point and r is radius
If radius r is decreased then also (h,k) remains same, only r² increases
Equation given in question is x² + y² + Cx + Dx + E=0
So, C and D will remain same but E will increase
 
        
             
        
        
        
Yes, parallelogram congruent angles theorem