Answer:
30 m^2.
Step-by-step explanation:
This  is a right-angled triangle because it obeys the Pythagoras theorem
 ( 13^2 = 12^2 + 5^2).
So its area = 1/2 * base * height 
= 1/2 * 5 * 12
= 30 m^2
 
        
             
        
        
        
Ok... so this question can be solved by using simultaneous equations. 
Use the general from of a parabola 

you know the value of c, the y-intercept... y = -4
which means the equation is 

now use the other 2 points to get 2 equations in 2 unknowns
(-2, -20) just substitute 

this becomes

now the other equation using (4, -20)
The simplified form is