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3 years ago

Do the ratios 4:12 and 5:15 form a proportion

Mathematics

2 answers:

guajiro [1.7K]3 years ago

8 0

Answer is up here ^^^

Strike441 [17]3 years ago

5 0

Answer:

4:12=5:15

in propotion form

4/12=5/15

Step-by-step explanation:

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Bernard designs motorized bicycles at Smart Gear Technologies. His total earnings are

olganol [36]

Answer: $43146

Step-by-step explanation:

So his total earning is $54,000. He has to pay $201 for every $1,000 he earns. So 54,000/1,000= 54. So now he has to pay 54*201=10854, 54000-10854=43146. His net income for this year is $43146.

8 0

3 years ago

A norman window is constructed by adjoining a semicircle to the top of an ordinary rectangular. Find the dimensions of a norman

Yanka [14]

Answer:

$W\approx 8.72$ and $L\approx 15.57$ .

Step-by-step explanation:

Please find the attachment.

We have been given that a norman window is constructed by adjoining a semicircle to the top of an ordinary rectangular. The total perimeter is 38 feet.

The perimeter of the window will be equal to three sides of rectangle plus half the perimeter of circle. We can represent our given information in an equation as:

$2L+W+\frac{1}{2}(2\pi r)=38$

We can see that diameter of semicircle is W. We know that diameter is twice the radius, so we will get:

$2L+W+\frac{1}{2}(2r\pi)=38$

$2L+W+\frac{\pi}{2}W=38$

Let us find area of window equation as:

$\text{Area}=W\cdot L+\frac{1}{2}(\pi r^2)$

$\text{Area}=W\cdot L+\frac{1}{2}(\pi (\frac{W}{2})^2)$

$\text{Area}=W\cdot L+\frac{\pi}{2}(\frac{W}{2})^2)$

$\text{Area}=W\cdot L+\frac{\pi}{2}(\frac{W^2}{4})$

$\text{Area}=W\cdot L+\frac{\pi}{8}W^2$

Now, we will solve for L is terms W from perimeter equation as:

$L=38-(W+\frac{\pi }{2}W)$

Substitute this value in area equation:

$A=W\cdot (38-W-\frac{\pi }{2}W)+\frac{\pi}{8}W^2$

Since we need the area of window to maximize, so we need to optimize area equation.

$A=W\cdot (38-W-\frac{\pi }{2}W)+\frac{\pi}{8}W^2$

$A=38W-W^2-\frac{\pi }{2}W^2+\frac{\pi}{8}W^2$

Let us find derivative of area equation as:

$A'=38-2W-\frac{2\pi }{2}W+\frac{2\pi}{8}W$

$A'=38-2W-\pi W+\frac{\pi}{4}W$

$A'=38-2W-\frac{4\pi W}{4}+\frac{\pi}{4}W$

$A'=38-2W-\frac{3\pi W}{4}$

To find maxima, we will equate first derivative equal to 0 as:

$38-2W-\frac{3\pi W}{4}=0$

$-2W-\frac{3\pi W}{4}=-38$

$\frac{-8W-3\pi W}{4}=-38$

$\frac{-8W-3\pi W}{4}*4=-38*4$

$-8W-3\pi W=-152$

$8W+3\pi W=152$

$W(8+3\pi)=152$

$W=\frac{152}{8+3\pi}$

$W=8.723210$

$W\approx 8.72$

Upon substituting $W=8.723210$ in equation $L=38-(W+\frac{\pi }{2}W)$ , we will get:

$L=38-(8.723210+\frac{\pi }{2}8.723210)$

$L=38-(8.723210+\frac{8.723210\pi }{2})$

$L=38-(8.723210+\frac{27.40477245}{2})$

$L=38-(8.723210+13.70238622)$

$L=38-(22.42559622)$

$L=15.57440378$

$L\approx 15.57$

Therefore, the dimensions of the window that will maximize the area would be $W\approx 8.72$ and $L\approx 15.57$ .

8 0

3 years ago

<img src="https://tex.z-dn.net/?f=%5Cfrac%7B5%7D%7B2%7D%20%3D%20%5Cfrac%7Bx%20-%204%7D%7B3%7D" id="TexFormula1" title="\frac{5}{

valentina_108 [34]

Step-by-step explanation:

$\frac{5}{2} = \frac{x - 4}{3}$

$3 \times \frac{5}{2} = \frac{x - 4}{3}$

$\frac{3}{1} \times \frac{5}{2} = \frac{x - 4}{3}$

cross multiplication

$\frac{6 \times 5}{2} = \frac{x - 4}{3}$

$15 = \frac{x - 4}{3}$

$15 \times 3 = x - 4$

$45 + 4 = x$

$49 = x$

4 0

3 years ago

Read 2 more answers

5/9 × 6 will the product be more or less than 2/9

8_murik_8 [283]

The product is 3.3333333333333 so less. hope this was helpfull

4 0

3 years ago

Read 2 more answers

Given: 1; -5; -13 ; -23 ; ...<br><br> Derive a formula for the nth term in the pattern.

mylen [45]

Answer:

f(n) = -n^2 -3n +5

Step-by-step explanation:

Suppose the formula is ...

f(n) = an^2 +bn +c

Then we have ...

f(1) = 1 = a(1^2) +b(1) +c

f(2) = -5 = a(2^2) +b(2) +c

f(3) = -13 = a(3^2) +b(3) +c

Here's a way to solve these equations.

Subtract the first equation from the second:

-6 = 3a +b . . . . . 4th equation

Subtract the second equation from the third:

-8 = 5a +b . . . . . 5th equation

Subtract the fourth equation from the fifth:

-2 = 2a

a = -1

Then substituting into the 4th equation to find b, we have ...

-6 = 3(-1) +b

-3 = b

and ...

1 = -1 +(-3) +c . . . . . substituting "a" and "b" into the first equation

5 = c

The formula is ...

f(n) = -n^2 -3n +5

3 0

4 years ago