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balandron [24]
3 years ago
8

The area of the shaded segment is 100cm^2. Calculate the value of r.

Mathematics
2 answers:
Reil [10]3 years ago
7 0
Hello, 

The formula for finding the area of a circular region is: A=  \frac{ \alpha *r^{2} }{2}

then:
A_{1} = \frac{80*r^{2} }{2}

With the two radius it is formed an isosceles triangle, so, we must obtain its area, but first we obtain the height and the base.

cos(40)= \frac{h}{r}  \\  \\ h= r*cos(40)\\ \\ \\ sen(40)= \frac{b}{r} \\ \\ b=r*sen(40)

Now we can find its area:
A_{2}=2* \frac{b*h}{2}  \\  \\ A_{2}= [r*sen(40)][r*cos(40)]\\  \\A_{2}= r^{2}*sen(40)*cos(40)

The subtraction of the two areas is 100cm^2, then:

A_{1}-A_{2}=100cm^{2} \\ (40*r^{2})-(r^{2}*sen(40)*cos(40) )=100cm^{2} \\ 39.51r^{2}=100cm^{2} \\ r^{2}=2.53cm^{2} \\ r=1.59cm

Answer: r= 1.59cm
puteri [66]3 years ago
5 0
Ok so we need to subtract the area of the triangle from the area of the segment and this will equal 100.
We know that the area of the segment is:
\frac{80}{360} * \pi r^{2}
And that the area of the triangle is:
\frac{1}{2} r^{2} sin(80)
Therefore:
\frac{80}{360} * \pi r^{2} - \frac{1}{2} r^{2} sin(80)=100
We can simplify it through these steps:
\frac{80}{360} * \pi r^{2} - \frac{1}{2} r^{2} sin(80)=100
4 \pi r^{2} - 9 r^{2} sin(80)=1800
r^{2}(4 \pi -9sin(80))=1800
r^{2} = \frac{1800}{4 \pi -9sin(80)}
r= \sqrt{\frac{1800}{4 \pi -9sin(80)} }
Therefore r=22.04cm (4sf)
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irga5000 [103]

Luke started a weight-loss program.

The first week, he lost X pounds.

the second week he lost 3/2 pounds less then 3/2 times the pounds he lost the first week. so, he lost 3/2 x - 3/2

The third week, he lost 1 more pound than 3/4 of the pounds he lost the first week. so, he lost 3/4 x + 1

So, over 3 weeks he lost :

x + (3/2 x - 3/2) + (3/4 x + 1) = 13/4 x - 1/2

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Liam started the program when Luke did.

The first week, he lost 1 pound less than 3/2 times the pounds luke lost the first week. so, he lost (3/2 x - 1)

The second week, he lost 4 pounds less than 5/2 times the pounds luke lost the first week. so ,he lost (5/2 x - 4)

The third week, he lost 1/2 more than 5/4 times the pounds luke lost the first week. so, he lost, ( 5/4 x + 1/2)

The expression for Liam's weight loss over the three weeks is =

= (3/2 x - 1) + (5/2 x - 4) + ( 5/4 x + 1/2) = 21/4 x - 9/2

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Assuming they both lost the same number of pounds over the three weeks

So, equating the number of pounds lost by each one of them

so,

13/4 x - 1/2 = 21/4 x - 9/2

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13/4 x - 21/4 x = -9/2 + 1/2

-2x = -4

divide both sides by -2

so,

x = -4/-2 = 2

so,

The number of pounds luke lost in the fist week is 2 pounds

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4. The number of pounds luke and liam each lost over the three weeks is

= 13/4 * 2 - 1/2 = 6 pounds

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1 year ago
Write an equation for the polynomial graphed below
Anit [1.1K]

The expression for the polynomial graphed will be y(x) = (x + 3)(x - 1 )(x - 4 ).

<h3>How to factor the polynomial?</h3>

From the graph, the zeros of the polynomial of given graph are:

x = -3

x = 1

x = 4

Equate the above equations to zero

x + 3 = 0

x - 1 = 0

x - 4 = 0

Multiply the equations

(x + 3)(x - 1 )(x - 4 ) = 0

Express as a function gives;

y = (x + 3)(x - 1 )(x - 4 )

Hence, the factored form of the polynomial will be y = (x + 3)(x - 1 )(x - 4 ) .

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Find x for each of these triangles please
notka56 [123]

Answer:

8) 10°

9) X can not be determined.

10) 10°

11) 12 units.

Step-by-step explanation:

8) The three sides of the given triangle are equal. Hence, the triangle is an equilateral triangle, hence each angle will be 60°.

So, 6x = 60°  

⇒ x = 10°.

9) The three angles of the given triangle are equal. Hence, the triangle is an equilateral triangle, hence each side will be equal.

So, 6x - 5 = 6x

So, x can not be determined from this equation.

10) Δ KLM is equilateral, so, KN will bisect ∠ MKL. So, ∠ NKL = 30°

Hence, 3x = 30°

⇒ x = 10°

11) In Δ XYZ, XZ = XY , so, ∠ Z = ∠ Y.

Again, ∠ X is given to be 60°.

Therefore, each angle is 60°.

So, the triangle XYZ is equilateral, and each side will be equal.

So, 3x + 8 = 4x - 4

⇒ x = 12 units. (Answer)

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3 years ago
Is 3 x 1/2 greater than 5?
Kryger [21]
No it is not greater than 5

When ever you are multiply a number by 1/2 you are halving the number. So in the us case 3 x 1/2 is 1.5.

And 1.5 is not greater than 5

So the answer is no



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3 years ago
Question and choices are in the photo please explain the answer
Natasha_Volkova [10]

Answer:

\text{A) }68\:\mathrm{cm}

Step-by-step explanation:

The perimeter of a polygon is equal to the sum of all the sides of the polygon. Quadrilateral PTOS consists of sides TP, SP, TO, and SO.

Since TO and SO are both radii of the circle, they must be equal. Thus, since TO is given as 10 cm, SO will also be 10 cm.

To find TP and SP, we can use the Pythagorean Theorem. Since they are tangents, they intersect the circle at a 90^{\circ}, creating right triangles \triangle TOP and \triangle SOP.

The Pythagorean Theorem states that the following is true for any right triangle:

a^2+b^2=c^2, where c is the hypotenuse, or the longest side, of the triangle

Thus, we have:

10^2+TP^2=26^2,\\TP^2=26^2-10^2,\\TP^2=\sqrt{576},\\TP=24

Since both TP and SP are tangents of the circle and extend to the same point P, they will be equal.

What we know:

  • TP=SP=24
  • TO=SO=10

Thus, the perimeter of the quadrilateral PTOS is equal to 24+24+10+10=\boxed{\text{A) }68\:\mathrm{cm}}

7 0
3 years ago
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