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3 years ago

How do you find the circumference, radius, and diameter?

Mathematics

1 answer:

igor_vitrenko [27]3 years ago

4 0

Check the picture below.

$\bf \textit{circumference of a circle}\\\\ C=2\pi r~~ \begin{cases} r=radius\\[-0.5em] \hrulefill\\ r=2.9 \end{cases}\implies C=2\pi (2.9)\implies C=5.8\pi \implies C\approx 18.22 \\\\[-0.35em] ~\dotfill\\\\ ~\hfill \stackrel{C\div r}{18.22\div 2.9 \approx 6.28}\qquad \stackrel{C\div d}{18.22\div 5.8 \approx 3.14}~\hfill$

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Can you explain how to do 13 please

Zigmanuir [339]

I must confess that I was about to pass this question by, but I was captured by the respectful and dignified way in which you asked for help.

A careful reading of the problem gives you two equations in two unknowns, which you can then solve as simultaneous equations. Here's how it looks:

Call 'C' the price of the senior Citizen ticket.
Call 'S' the price of the Student ticket.

On the first night . . . 10 C + 12 S = 208

On the second night . . . 8C + 3 S = 74

Those are your two simultaneous equations. Now the idea is to multiply or divide each side of one equation in such a way that when you add or subtract it from the other equation, one of the variables will become a zero quantity ... you'll be left with an equation in one variable, which you can easily solve. THEN, knowing the value of one variable, you can put it back into one of the original equations,and find the value of the other variable.

This all sounds more complicated than it is. Here's how it goes:
We have . . .

10 C + 12 S = 208 and
8C + 3 S = 74

I'm going to multiply each side of the second equation by 4, and then write it under the first one:

10 C + 12 S = 208
32 C + 12 S = 296

Now, subtract the lower equation from the upper one, and you get . . .

- 22 C + 0 = - 88

Divide each side of this one by -22 and you have C = $4.00 .

THAT's what you need, to blow the whole problem wide open. Knowing
the value of 'C', let's substitute it into the equation for the first night:

10 C + 12 S = 208

10(4) + 12 S = 208

40 + 12 S = 208

Subtract 40 from each side : 12 S = 168

Divide each side by 12 : S = $ 14.00 .

Finally, as we look over our results, and see that Students have to pay $14 to see the show but Seniors can get in for only $4 , we reflect on this ... or at least I do ... and realize that getting old is not necessarily all bad.

3 0

3 years ago

What is the sum of 20x^2-10x-30

ivann1987 [24]

Answer:

The sum of the roots is 0.5

Step-by-step explanation:

The correct question is

What is the sum of the roots of 20x^2-10x-30

we know that

In a quadratic equation of the form

$ax^{2} +bx+c=0$

The sum of the roots is equal to

$-\frac{b} {a}$

in this problem we have

$20x^{2} -10x-30=0$

$a=20\\b=-10\\c=-30$

substitute

$-\frac{(-10)} {20}=0.5$

Verify

Find the roots of the quadratic equation

The formula to solve a quadratic equation is equal to

$x=\frac{-b\pm\sqrt{b^{2}-4ac}} {2a}$

$a=20\\b=-10\\c=-30$

substitute

$x=\frac{-(-10)\pm\sqrt{-10^{2}-4(20)(-30)}} {2(20)}$

$x=\frac{10\pm\sqrt{2,500}} {40}$

$x=\frac{10\pm50} {40}$

$x=\frac{10+50} {40}=1.5$

$x=\frac{10-50} {40}=-1$

The roots are x=-1 and x=1.5

The sum of the roots are

$-1+1.5=0.5$ ----> is ok

5 0

3 years ago

Can someone please give me the answer I will mark u brilliant as soon as it pops up.

adelina 88 [10]

9514 1404 393

Answer:

(a) 26 units

Step-by-step explanation:

The left-side vertical line extends from y = -3 to y = +3, so is 3-(-3) = 6 units long.

The bottom side horizontal line extends from x = -5 to x = 2, so is 2 -(-5) - 7 units long.

The sum of these two sides is 6 + 7 = 13 units. These two sides make up half of the perimeter, which is the total length of all four sides.

The perimeter is 2 × 13 units = 26 units.

7 0

3 years ago

In a science experiment,the temperature decreased by 0.1 degree Celsius every 15 minutes. Find the unit rate

maksim [4K]

0.1 decrease in 15 minutes
unit rate is 0.1 / 15 = 0.00667
Temperature is decreasing by 0.00667 degrees Celsius per minute

8 0

3 years ago

In which place is the digit in the number 5,341 that would be changed to form 5,841? How do the values of the two numbers compar

Colt1911 [192]

We want to change the digit in the number 5,341 into 5,841, and to find the difference between the numbers.

Refer to the figure shown below.
The number 3 is in the 3rd place (hundreds) of the number 5,341 as a digit.
It is replaced by 8 to form the number 5,841.

This means that 300 is replaced by 800 because, in the third place, we count by hundreds in the 3rd place.
The difference between 800 and 300 is 500.

Subtraction of 5,341 from 5,841 also yields 500.

Answer:
The digit is in the 3rd place (hundreds).
The difference between the numbers is 500.

3 0

3 years ago