Are these 2 triangles congruent? 0 If no, type "not congruent" If yes, state what postulate or theorem proves it.

8 Leandra's fastest time for the 400 m is 70 seconds. In his next race he improves by

disa [49]

8) a) The new fastest time is 56.7 seconds, b) The <em>overall percentage</em> improvement is 19 %.

9) The height after the first increase is 1.375 meters and after the second increase is 1.54 meters.

<h3>How to apply percentages in real life applications</h3>

In this problem we have two examples from real life, in which percentages are used. The first is the distance traveled by a runner in a given time and the second is the growth of a person in time. Change in variables based on percentages are described by the following formula:

C' = C · (1 + r / 100) (1)

Where:

C - Initial value
C' - Final value
r - Percentage of change.

Now we proceed to resolve on each case. 8) a) Please notice that the runner must cover the trail in less time and percentage time must be negative. If we know that C = 70 and r = - 10, then his new fastest time is:

C' = 70 · (1 - 10 / 100)

C' = 70 · 0.90

C' = 63

And again: (C' = 63, r = - 10)

C'' = 63 · (1 - 10 / 100)

C'' = 63 · 0.90

C'' = 56.7

The new fastest time is 56.7 seconds.

b) And the overall percentage improvement is:

r = (|C'' - C| / C) × 100 %

r = (|56.7 - 70| / 70) × 100 %

r = 19 %

The <em>overall percentage</em> improvement is 19 %.

9) If we know that C = 1.25 and r = 10, then the height next year is:

C' = 1.25 · (1 + 10 / 100)

C' = 1.375

And again: (C' = 1.375, r = 12)

C'' = 1.375 · (1 + 12 / 100)

C'' = 1.54

The height after the first increase is 1.375 meters and after the second increase is 1.54 meters.

To learn more on percentages: brainly.com/question/13450942

#SPJ1

3 0

2 years ago

Packaging By cutting away identical squares from each corner of a rectangular piece of cardboard and folding up the resulting fl

Vikki [24]

Answer:

Height: 3/2 inches

Length: 12 inches

Width: 4 inches

Step-by-step explanation:

Let x is the side length of the square

The height of the box by cutting squares off :x

The new length of the cardboard = 15 -2x (because we cut from 4 corners)
The new width of the cardboard = 7 -2x (because we cut from 4 corners)

The new volume of it is:

V = (15 -2x) (7 -2x) x

<=> V = $4x^3 -44x^2 +105x$

To maximum volume, we use the first derivative of the volume

$\dfrac{dV}{dx} = 0$

<=> $12x^2-88x+105=0$

<=> $\left(2x-3\right)\left(6x-35\right) = 0$

<=> 2x -3 = 0 or 6x -35 = 0

<=> x = 3/2 or x = 35/6

To determine which value of x gives a maximum, we evaluate

$\dfrac{d^2V}{dx^2}$ = 24x -88

If x = 3/2, we have:

$\dfrac{d^2V}{dx^2}$ = 24(3/2) -88 = -52

If x = 35/6, we have:

$\dfrac{d^2V}{dx^2}$ = 24(35/6) -88 = 52

We choose x = 3/2 to have the maximum volume because the value of x that gives a negative value is maximum.

So the dimensions (in inches) of the box is:

Height: 3/2 inches

Length: 15-2(3/2) = 12 inches

Width: 7 - 2(3/2) = 4 inches

5 0

2 years ago

Plugin y=-5 into either equation and solve for x<br> -6x-8y=-20 or x+y=5

nalin [4]

Answer:

x = 10

Step-by-step explanation:

3 0

2 years ago

Read 2 more answers

Subtract.

Yakvenalex [24]

1345 - (-853) = D) 2198.

Simplify your brackets to get: 1345 + 853 and then add which will get you your answer, 2198.

8 0

3 years ago

Read 2 more answers

Please help me , I don’t understand :(

Yuri [45]

Answer:

A. 1.4 times

Step-by-step explanation:

The factor in this exponential function is 1.4.

Please see the attachment.

7 0

3 years ago

Are these 2 triangles congruent? 0 If no, type "not congruent" If yes, state what postulate or theorem proves it.​

Are these 2 triangles congruent? 0 If no, type "not congruent" If yes, state what postulate or theorem proves it.