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2 years ago

Percent decrease 95 to 15

Mathematics

1 answer:

scZoUnD [109]2 years ago

5 0

Answer:

84.2105263 % decrease

Step-by-step explanation:

Take the original and subtract the new

95-15 = 80

Divide by the original

80/95

.842105263

Change to percent form

84.2105263 % decrease

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A rocket is launched straight up from the ground with an initial velocity of 192 feet per second. The equation for the height of

Ivenika [448]

The equation for the height of the rocket at time t given

$h= -16t^2+192t$

We have to find the time t, when the rocket reaches 560 feet.

That means we have to find t when h = 560 ft. we will place 560 in the place of h to find t now.

$h= -16t^2+192t$

$560 = -16t^2+192t$

In the right side, we can check -16 is the common factor. So we will take out -16 from the rigbht side.

$560 = -16(t^2 - 12t)$

To get rid of -16 from the right side and move it to left side, we will divide both sides by -16.

$560/-16 = -16(t^2-12t)/-16$

$-35 = t^2 -12t$

Now we will move -35 to the righ side by adding 35 to both sides.

$-35+35 = t^2-12t+35$

$0 = t^2 -12t+35$

$t^2-12t+35 = 0$

We will factorize thee left side to find the values of t now. We need to find a pair of factors of 35 that by adding them we will get -12.

The pair of factors of 35 are -5 and -7 and by adding -5-7 we will get -12.

$t^2-12t+35 =0$

$(t-5)(t-7) =0$

So by using zero product property we will get

$t-5 =0$

$t-5+5 = 0+5$

$t=5$

Also $t-7 =0$

$t-7+7 = 0+7$

$t=7$

So we have got the rocket reaches at 560ft when t = 5 seconds and also when t = 7 seconds.

Now part b.

When the rocket completes its trajectory and hits the ground then the height or h = 0. So we will place h = 0 there in the equation.

$h= -16t^2+192t$

$0= -16t^2 + 192 t$

$0 = -16(t^2-12t)$

$-16(t^2-12t) = 0$

We will move -16 to the other side by dividing it to both sides.

$-16(t^2-12t)/-16 = 0/-16$

$t^2-12t = 0$

We will take out the common factor t from the left side. By taking out t we will get,

$t(t-12) = 0$

We will use zero product property now. By using that we will get,

$t = 0$

ans also $t-12 = 0$

$t-12+12 = 0+12$

$t = 12$

When the rocket completes its trajectory and hits the ground the time t can not be 0. When t =0, the rocket starts the trajectory.

So when the rocket completes its trajectory and hits the ground ,

then t = 12seconds.

So we have got the required answers.

6 0

2 years ago

The area of a rectangle is 42 square feet.

Alchen [17]

Answer:

26 ft and 46 ft.

Step-by-step explanation:

The prime factors of 42 are 2 * 3 * 7.

Possible lengths and widths are:

L = 7, W = 6 giving a perimeter of 2*7 + 2*6 = 26 ft.

L = 14 , W = 3 giving perimeter = 34 ft.

L = 21, W = 2 giving perimeter = 46 ft.

3 0

2 years ago

Marco has drawn a line to represent the perpendicular cross-section of the triangular prism. Is he correct? Explain. triangular

evablogger [386]

Answer:

The correct option is;

Yes, the line should be perpendicular to one of the rectangular faces

Step-by-step explanation:

The given information are;

A triangular prism lying on a rectangular base and a line drawn along the slant height

A perpendicular bisector should therefore be perpendicular with reference to the base of the triangular prism such that the cross section will be congruent to the triangular faces

Therefore Marco is correct and the correct option is yes, the line should be perpendicular to one of the rectangular faces (the face the prism is lying on).