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3 years ago

What is the radius of a circle with an area of 78.5 cubic inches? use 3.14 for pie

Mathematics

2 answers:

svetlana [45]3 years ago

6 0

Answer:

radius = 5 in

Step-by-step explanation:

Using the formula for calculating the area (A) of a circle

A = πr² ( r is the radius )

here A = 78.5, hence

3.14r² = 78.5 ( divide both sides by 3.14 )

r² = $\frac{78.5}{3.14}$ = 25 ( take the square root of both sides )

r = $\sqrt{25}$ = 5

Harman [31]3 years ago

3 0

Answer:

The radius is 5 in

Step-by-step explanation:

The area of a circle is given by the formula

A = pi *r^2

We know the area = 78.5 in^2 (volume would be in^3 area is in^2)

78.5 = 3.14*r^2

Divide each side by 3.14

78.5/3.14 = 3.14/3.14*r^2

25 = r^2

Take the square root of each side

sqrt(25) sqrt(r^2)

5 =r

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We could take, for example:

$\begin{cases}x\geq-3\\y\geq3\end{cases}$

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For y ≥ 3 we have horizontal line (y-intercept = 3) and shaded region above that line.

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Simply, substitute x and y coordinates of D and E <span>to the system of inequalities from part A, and check if its is true, what we get.
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and point E is also a solution to <span>our system of inequalities.
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Part C.

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B=(-4,-2)\\\\y\ \textless \ 3x-3\quad\implies\quad-2\ \textless \ 3\cdot(-4)-3\quad\implies\quad-2\ \textless \ -15\quad\text{False}\\\\\\
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D=(-2,4)\\\\y\ \textless \ 3x-3\quad\implies\quad4\ \textless \ 3\cdot(-2)-3\quad\implies\quad4\ \textless \ -9\quad\text{False}\\\\\\
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$F=(3,-4)\\\\y\ \textless \ 3x-3\quad\implies\quad-4\ \textless \ 3\cdot3-3\quad\implies\quad-4\ \textless \ 6\quad\text{True}\\\\\\$

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