Answer:
t = 4 seconds
Step-by-step explanation:
The height of the projectile after it is launched is given by the function :

t is time in seconds
We need to find after how many seconds will the projectile land back on the ground. When it land, h(t)=0
So,

The above is a quadratic equation. It can be solved by the formula as follows :

Here, a = -16, b = 32 and c = 128

Neglecting negative value, the projectile will land after 4 seconds.
Answers:
1. V=triangle area × length
V=1/2×8×12×20
V=960in³
2. triangle area × length
Area of the triangle=1/2×4×11
A=22ft²
V=22×6
V=132ft³
3. b, volume always have cubic power (³)
4. d, same reason of question 3
Smaller Angle: 49 degrees
Bigger Angle: 131 degrees
Note that supplementary angles add up to be 180 degrees. Knowing this and the information provided in the question, we can use the following system of equations:
x + y = 180 (showing they both add up to 180)
x + 82 = y (to show one angle is 82 more than the other)
We can use the substitution method to solve. Since the second equation ends in "= y" we can substitute the value of it into y for the first equation.
x + y = 180; x + 82 = y ==> x + (x + 82) = 180
And now, solve for x:
x + (x + 82) = 180
x + x + 82 = 180 > combine like terms
2x + 82 = 180
2x = 98
x = 49
So now we have the value for one of the angles! Remembering that the other angle is 82 degrees bigger, dd 49 + 82, which equals 131.
So, our two angle values are 131 and 49! This is correct since both angle measures add up to be 180, which also makes them supplementary!