Respuesta :
Answer :- t > 6.25 would be the interval of time is he within 104 feet above the ground.
Explanation:-
Given equation:-[tex]h=-16t^2+729[/tex], where t is the time in seconds.
For the interval that he is at height within 104 feet above the ground.[tex]0<-16t^2+729<104[/tex]
[tex]-16t^2+729<104\\\Rightarrow\ -16t^2<104-729........[\text{subtract 729 both sides}]\\\Rightarrow-16t^2<-625\\\Rightarrow\ 16t^2>625....[\text{multiply -1 on both sides}]\\\Rightarrow\ 4t>25\text{ or }4t<-25....[\text{take square root on both sides}]\\\Rightarrow\ t>6.25\text{ or }t>-6.25..[\text{divide 4 on both sides}][/tex]
And time cannot be negative
Thus at t>6.25 seconds,for height= 104 feet above the ground.
⇒The interval of time is he within 104 feet above the ground
would be t > 6.25 .

Answer:
t >6.25
Step-by-step explanation:
Given : [tex]h = -16t^{2} +729[/tex]
To Find: for which interval of time is he within 104 feet above the ground?
Solution ;
[tex]h = -16t^{2} +729[/tex]
Since we are required to find for which interval of time is he within 104 feet above the ground
So,
[tex]-16t^{2} +729<104[/tex]
[tex]-16t^{2} <104-729[/tex]
[tex]-16t^{2} < -625[/tex]
[tex]16t^{2}>625[/tex]
[tex]t^{2} >\frac{625}{16}[/tex]
[tex]t >\sqrt{39.0625}[/tex]
[tex]t >6.25[/tex]
Thus for t >6.25 he is within 104 feet above the ground