36 hours use cross multiplication
Answer: 25
Step-by-step explanation: got it wrong and got the answer Took 1 for the team
Answer:
The pebble will hit the ground 8.29 second after it is thrown.
Step-by-step explanation:
Given that,
The height of the pebble after t seconds is given by the equation
h= -16t²+24 t+900.
When the pebble hit the ground, the height of the pebble will be zero.
So putting h=0 in the given equation.
0 = -16t²+24 t+900
⇒-4(4t²-6t-225)=0
⇒4t²-6t-225=0
Applying quadratic formula
, here a=4, b= -6 and c= -225.

⇒ t = 8.29, -6.79
Since time can not negative.
∴t=8.29 seconds.
The pebble will hit the ground 8.29 second after it is thrown.
Answer:
A choice
Step-by-step explanation:
sec is defined as 1/cos.
cos is again defined as adjacent to hypotenuse.
We know that adjacent is x and hypotenuse is r.
Therefore:- cos is x/r
Now sec is 1/cos = 1/(x/r)
1 ÷ x/r is 1•r/x
Thus:-
sec is r/x