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3 years ago

HI PLS HELP ITS DUE AT 12 AND ITS 11:45 WILL MARK BRAINLIEST

Mathematics

1 answer:

OlgaM077 [116]3 years ago

3 0

Answer:

Answer = 3.14 * 40 = 125.6m^2

Step-by-step explanation:

Let R be the greater radius and r be the smaller radius

A) Area of the sidewalk = \pi R^2 - \pi r^2 - This can be the expression

B) pi = 3.14

= pi (R^2-r^2)

= pi (11^2-9^2)

= pi (121-81)

= pi *40

That was the simplified expression

Answer = 3.14 * 40 = 125.6m^2

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A rectangular storage container with an open top is to have a volume of 10 m3. The length of this base is twice the width. Mater

noname [10]

Answer:

$ 327.08

Step-by-step explanation:

Let w be the width ( in meters ) of the container,

⇒ Length of the container = 2w,

If h be the height of the container,

So, the volume of the container = length × width × height

= 2w × w × h

= 2w² h

According to the question,

$2w^2h=10$

$\implies h=\frac{10}{2w^2}=\frac{5}{w^2}$

Now, the area of the base = length × width

$=2w^2$

Area of sides = 2 × length × height + 2 × width × height

$=2\times 2w\times h+2\times w\times h$

$=4w\times \frac{5}{w^2}+2w\times \frac{5}{w^2}$

$=\frac{20}{w}+\frac{10}{w}$

$=\frac{30}{w}$

Since, material for the base costs $20 per square meter and material for the sides costs $12 per square meter,

Hence, total cost,

$C(w) = 2w^2\times 20 +\frac{30}{w}\times 12$

$C(w)=40w^2+\frac{360}{w}$

Differentiating with respect to w,

$C'(w) = 80w - \frac{360}{w^2}$

Again differentiating with respect to w,

$C''(w) = 80 +\frac{720}{w^3}$

For maxima or minima,

C'(w) = 0

$80w - \frac{360}{w^2}=0$

$80w^3-360=0$

$80w^3=360$

$\implies w=\sqrt[3]{\frac{360}{80}}=1.65096362445\approx 1.651$

For w = 1.651, C''(w) = positive,

Thus, cost is minimum for width 1.651 meters,

And, the minimum cost = C(1.651) = $40(1.651)^2+\frac{360}{1.651}=\$327.081706869\approx \$ 327.08$

3 0

4 years ago

In a race that consisted of three parts the cycling part was 12 1/2 miles long the running part of the race was won for the dist

Nata [24]

Complete question is;

In a race that consisted of three parts, the cycling part was 12 1/2 miles long. The running part of the race was 1/4 the distance of the cycling part. The kayaking part of the race was 1/2 the distance of the running part. What was the entire distance, in miles of the race?

Answer:

Total distance of race = 17.1875 miles

Step-by-step explanation:

The 3 parts of the race are; cycling, running and kayaking.

The cycling distance was; 12½ miles

We are told that the running part was ¼ of the cycling distance. Thus;

Running distance = ¼ x 12½ = ¼ x 25/2 = 25/8 miles

Lastly, we are told that the kayaking part was ½ the distance of the running part. Thus;

Kayaking distance = ½ x 25/8 = 25/16

Thus,total distance of race = cycling distance + running distance + kayaking distance = 12½ + 25/8 + 25/16 = 17.1875 miles

4 0

3 years ago

What is 100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

Allisa [31]

Answer:

Step-by-step explanation:

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3 0

3 years ago

If a day was a year, how many does it take to make a million years?

Tasya [4]

It would take 2,740 days to make a million years.

1,000,000 divided by 365.

6 0

4 years ago

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The city of Odessa, Texas is building a wheelchair ramp to make their courthouse accessible for persons in a wheel chair. The Am

LuckyWell [14K]

Answer:

No they will not have to install a rest platform.

The ramp will be 29.88 feet long so they will not have to install a rest platform.

Step-by-step explanation:

4 0

3 years ago