Answer:
31. (a) The height decreases by 12 feet each second towards the first floor
(b)
- After 3 seconds, the elevator is 144 feet above the first floor
- After 6 seconds, the elevator is 108 feet above the first floor
- After 9 seconds, the elevator is 72 feet above the first floor
(c) It takes 15 seconds for the elevator to get to the first floor
(d) The basement floor is 48 feet below the first floor
Step-by-step explanation:
<u>31 (a) explanation:</u>
An elevator is 180 feet above the first floor.
Each second, it descends 12 feet.
So the elevator's change in height each second is a decrease of 12 feet towards the first floor.
<u>31 (b) explanation:</u>
If the elevator goes down 12 feet, towards the first floor, in 1 second then;
- After 3 seconds it will be 180 feet - 3(12) feet = 144 feet above the first floor
- After 6 seconds it will be 180 feet - 6(12) feet = 108 feet above the first floor
- After 9 seconds it will be 180 feet - 9(12) feet = 72 feet above the first floor
<u>31 (c) explanation:</u>
If the elevator is 180 feet above the first floor and it takes 1 second to descend 12 feet,
Then it will take: × 1 second = 15 seconds reach the first floor.
<u>31 (d) explanation:</u>
From the first floor it takes 4 seconds to reach the basement floor
Therefore the basement floor is × 12 feet = 48 feet below the first floor
Given that the length of the arc of the circle is, 9.5 ft, thus, the radius of the circle would be: 4.5 ft.
<h3>What is the Length of an Arc?</h3>
Length of arc of a circle = ∅/360 × 2πr
Radius = r.
Given:
∅ = 120°
Length of arc = 9.5 ft
Radius (r) = ?
Thus:
9.5 = 120/360 × 2× 3.14 × r
9.5 = 2.09r
r = 9.5/2.09
r = 4.5 ft
Learn more about length of arc on:
brainly.com/question/2005046
√36 = plus or minus 6. These results are real, rational, integer, whole and natural, and yes, there can be more than one answer; that's because we're solving a quadratic equation. Note that both 6 and -6, when squared, yield 36.
Answer:
2nd option
Step-by-step explanation:
The discriminant b² - 4ac tells us about the nature of the roots
• If b² - 4ac > 0 then 2 real and distinct roots
• If b² - 4ac = 0 then 2 real and equal roots
• If b² - 4ac < 0 then the roots are not real
Here b² - 4ac = 15 > 0
Then there are 2 real and distinct roots
x = 2 and x = - 3 are possible solutions to the equation
Answer:
r = 4
Step-by-step explanation:
Volume of a cone:
V = πr²(h/3)
Given:
V = 100.48
h = 6
π = 3.14
Work:
V = πr²(h/3)
100.48 = r²(3.14)(6/3)
100.48 = r²(3.14)(2)
100.48 = r²6.28
r² = 100.48/6.28
r² = 16
r = 4