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atroni [7]
3 years ago
13

A rock is thrown from the top of a tall building.The distance in feet between the rock and the ground t seconds after thrown is

given by d = -16t2 -4t + 412. How long after the rock is thrown is it 407 feet from the ground?
Mathematics
1 answer:
marusya05 [52]3 years ago
4 0

Answer:

0.448 seconds

Step-by-step explanation:

d = -16t² -4t + 412

find t when d = 407

substituting d = 407 into the equation:

407 = -16t² -4t + 412 (subtract 407 from both sides)

-16t² -4t + 412 - 407 = 0

-16t² -4t + 5 = 0 (multiply both sides by -1)

16t² + 4t - 5 = 0  

solving using your method of choice (i.e completing the square or using the quadratic equation), you will end up with

t = (-1/8) (1 + √21)= -0.70 seconds (not possible because time cannot be negative)

or

t = (-1/8) (1 -√21) = 0.448 seconds (answer)

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-6+3y=12 solve for x
Roman55 [17]

Answer:

The answer is y=6

Step-by-step explanation:

Move the constant to the right side and change its sign

3y=12+6

Add the numbers

12 +6

3y=18

Divide both sides of the equation by 3

Which equals

Y=6

Hope that helps

5 0
3 years ago
I really need help with this
aniked [119]

Answer:

5√202

Step-by-step explanation:

By Pythagoras theorem,

x^2 = 45^2 + 55^2

= 2025 + 3025

x^2 = 5050

x = 5√202

5 0
2 years ago
34 in.
Troyanec [42]

Answer:

Step-by-step explanation:

Lateral surface area of the triangular prism = Perimeter of the triangular base × Height

By applying Pythagoras theorem in ΔABC,

AC² = AB² + BC²

(34)² = (16)² + BC²

BC = \sqrt{1156-256}

     = \sqrt{900}

     = 30 in.

Perimeter of the triangular base = AB + BC + AC

                                                      = 16 + 30 + 34

                                                      = 80 in

Lateral surface area = 80 × 22

                                  = 1760 in²

Total Surface area = Lateral surface area + 2(Surface area of the triangular base)

Surface area of the triangular base = \frac{1}{2}(\text{Base})(\text{Height})

                                                           = \frac{1}{2}(30)(16)

                                                           = 240 in²

Total surface area = 1760 + 2(240)

                               = 1760 + 480

                               = 2240 in²

Volume = Area of the triangular base × Height

             = 240 × 20

             = 4800 in³

6 0
2 years ago
A. Solve for y.<br> B. What is the measure of the missing angles?
Alik [6]
Answer: A.) y = 15 B.) (5y + 3)° = 78° (4y + 8)° = 68° and 34°

Steps:
180° - 146° = 34°

180 = 34 + (5y + 3) + (4y + 8)
180 - 34 = (5y + 3) + (4y + 8)
146 = (5y + 3) + (4y + 8)
146 = 5y + 3 + 4y + 8
146 = 9y + 11
146 - 11 = 9y
135 = 9y
135/ 9 = y
15 = y

(5y + 3)
5(15) + 3
75 + 3
78
(5y + 3) = 78

(4y + 8)
4(15) + 8
60 + 8
68
68 = (4y + 8)

Check:
68 + 78 + 34 = 180
180 = 180 ✅
5 0
2 years ago
How can you find the number of feet in 1 million inches
Fofino [41]
There is exactly 8333.3333 feet in one million inches
7 0
3 years ago
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