Answer:
5secs
Step-by-step explanation:
Given the equation of the height expressed ad;
h(t) = - 16t^2 + initial height
Given that initial height = 400feet
h(t) = - 16t^2 + 400
The waste will hit the ground at when h(t) = 0
substitute
0 =  - 16t^2 + 400
16t^2 = 400
t² = 400/16
t² = 25
t = √25
t = 5secs
Hence it will take the easte 5secs to hit the ground
 
        
             
        
        
        
Answer:
18
Step-by-step explanation:
9+9=18 both sides of the rectangle is 9 so the top is longer which means 18