Answer:

Step-by-step explanation:
Cosine is the adjacent side over the hypotenuse (You can remember sin, cos, and tan by using sohcahtoa or sin = opposite/hypotenuse, cos = adjacent/hypotenuse, tan = opposite over adjacent). I think a picture would help, too.
I attached a picture of what I think the triangle would look like.
If the picture is right (we're assuming it is) and going with what we're given (the triangle was addressed as triangle XYZ, meaning that <u>angle Y is in the middle and that's the one we'll use</u>).
Looking at my picture then:
.
This is the concept of application of quadratic expressions. Given that the height of the ball is modeled by the equation;
h=-7.3t^2+8.25t+2.1+5
The time taken for the ball to hit the ground will be given as falls;
-7.3t^2+8.25t+7.1=0
to solve for t we use the quadratic formula;
t=[-b+/-sqrt(b^2-4ac)]/(2a)
a=-7.3, b=8.25, c=2.1
t=[-8.25+/-sqrt[8.25^2+4*7.3*7.1]/(-2*7.3)
t= -0.572
or
t=1.702
since there is not negative time we take the time taken for the ball to hit the ground will be: t=1.702 sec
Answer: what the other guy said 69
Step-by-step explanation:
Ok is easy first it takes 10mm =1cm 100cm=1m 1000mm=1km so you do 1.5 divided by 1000km=.0015 km so your answer is .0015km