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3 years ago

Martinbly.com

Mathematics

1 answer:

Lesechka [4]3 years ago

6 0

Answer:

55.5

Step-by-step explanation:

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Using a property of operations, what can you say about the sums of (-13.2) + 8.1 and 13.2 + (-8.1)

Wewaii [24]

They are opposites of each other.
-13.2 + 8.1 = -5.1
13.2 - 8.1 = 5.1

4 0

3 years ago

Following the lead of the National Wildlife Federation, the Department of the Interior of a South American country began to reco

chubhunter [2.5K]

Answer:

After 2009 the quality of the forests in this country improving.

Step-by-step explanation:

Consider the provided function.

$f(t) = \frac{1}{3}t^3-\frac{5}{2}t^2 + 80$

$f'(t) = t^2-5t$

Substitute f'(t)=0.

$t^2-5t=0$

$t(t-5)=0$

$t=0\ or\ t=5$

It is given that (0 ≤ t ≤ 10)

The test interval are (0,5) and (5,10)

For (0 < t < 5) the value of $f'(t)$

For (5 < t < 10) the value of $f'(t) >0$

Hence, the function is increasing from (5,10).

t = 0 corresponds to 2004.

Therefore, after 2009 the quality of the forests in this country improving.

7 0

3 years ago

A satellite is 19,000 miles from the horizon of Earth. Earth’s radius is about 4,000 miles. Find the approximate distance the sa

Jobisdone [24]

Answer:

The approximate distance is 15416 miles....

Step-by-step explanation:

We have given:

A satellite is 19,000 miles from the horizon of earth.

The radius is 4,000 miles.

Lets say that BC =x

AO = OB = 4,000 miles

AC = 19,000 miles

The tangent from the external point forms right angle with the radius of the circle.

So in ΔABC

(OC)² = (AC)²+(OA)²

where OC = x+4000

AC = 19,000

OA = 4000

Therefore,

(x+4000)² = (19,000)² +(4,000)²

Take square root at both sides:

√(x+4000)² = √(19,000)² +(4,000)²

x+4000 =√361000000+16000000

x+4000 = √377000000

x+4000 = 19416.48

x= 19416.48 - 4000

x = 15416.48

Therefore the approximate distance is 15416 miles....

6 0

3 years ago

Rebecca went swimming yesterday. After a while she had covered one fifth of her intended distance. After swimming six more lengt

alukav5142 [94]

Answer:

Option E.

Step-by-step explanation:

Let the intended length of Rebecca's swimming is = x units

and we assume the length of the pool = l units

Now it is given in the question that " She covers one fifth of her intended distance "

That means distance covered = $\frac{x}{5}$

" After swimming six more lengths of the pool she had covered one quarter of her intended distance"

So $\frac{x}{5}+6(l)=\frac{x}{4}$

$6l=\frac{x}{4}-\frac{x}{5}$

$6l=\frac{x}{20}$

x = 20×(6l)

x = 120l

Therefore, Rebecca has to complete 120 lengths of the pool.

Option E is the answer.

4 0

3 years ago

PLEASE HELP!!!!!! The length of a rectangle is three times its width. If the perimeter of the rectangle is 56 cm, find its area.

Alexus [3.1K]

Step-by-step explanation:

l = length

w = width

l = 3w

perimeter p = 2l + 2w = 56

using the identity of the first equation

p = 2(3w) + 2w = 56

6w + 2w = 56

8w = 56

w = 7 cm

l = 3w = 3×7 = 21 cm

so, the area is

l×w = 21×7 = 147 cm²

8 0

2 years ago