Let us assume then that the center is the origin.  If the major axis is 18, then a = 9 and a^2=81.  If the minor axis is 16, then b = 8 and b^2=64.  Now you can write the equation.  Remember that this ellipse is vertical and so a^2 goes under y^2
        
                    
             
        
        
        
Answer:
1st option
Step-by-step explanation:
The 2 angles are alternate exterior angles and are congruent , so
3x = 2x + 20 ( subtract 2x from both sides )
x = 20
 
        
             
        
        
        
For finding the perimeter of abc (triangle), we MUST need the two others coordinates of b and c
let b(1, 2) and c (2, -4)
we need to calculate the distances ab, ac, and bc
vector (ab)=(1-(-2), 2-9)=(3, -7), so its length is ab=sqrt(3²+ (-7)²)=7.61
realising the same method, we find bc=6.08, ac=13.60
so the perimeter of abc is P= ab+bc+ca=13.60+6.08+7.61=27.29