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3 years ago

Can someone please help with this

Mathematics

1 answer:

mash [69]3 years ago

3 0

Answer:

3. 43.96 cm

4. 81.64 ft

Step-by-step explanation:

3. The formula for the circumference of a circle in terms of radius is ...

C = 2πr

When π is approximated by 3.14, this becomes ...

C ≈ 6.28r

The only answer choice even close to 6.28×(7 cm) is the one shown above.

___

4. The formula for the circumference of a circle in terms of diameter is ...

C = πd

When π is approximated by 3.14, this becomes ...

C ≈ 3.14d

The only answer choice anywhere close to 3.14×(26 ft) is the one shown above.

_____

Comment on the solution

For questions like these, you only need to be able to estimate the answer to 1 or 2 significant digits. The answer choices are not so close together as to cause any confusion.

6×7 = 42, so the answer will be a few more than 42.

3×26 = 78, so the answer will be within a few numbers larger than that.

In each case, the answer is the largest value on the list. The other choices differ by a factor of 2, so aren't even close.

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Talja [164]

Answer:

135 minutes

Step-by-step explanation:

Let

y -----> the number of pages to finish reading the book

x ----> the number of hours

we know that

The linear equation in slope intercept form is equal to

$y=mx+b$

where

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In this problem we have

Xanthia

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$b=225\ pages$

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For y=0

substitute and solve for x

$0=-100x+225$

$100x=225$

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$m=50\ pages/hour$

$b=225\ pages$

$y=-50x+225$ ----> the slope is negative because is a decreasing function

For y=0

$0=-50x+225$

$50x=225$

$x=4.5\ hours$ --- Molly's time to finish reading the book

To find out how many more minutes than Xanthia would it take for Molly to finish reading the book, subtract Xanthia's time from Molly's time

$4.5\ h-2.25\ h=2.25\ h$

Convert to minutes

Multiply by 60

$2.25\ h=2.25(60)=135\ minutes$

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