6 cm 18 cm 35 cm 26 cm Calculate the volume of the solid

A circle is centered at the point (-7, -1) and passes through the point (8, 7).

Sergeu [11.5K]

we know the circle's center is at -7, -1, and we know the circle itself passes through 8,7, the distance from the center to a point on it is by definition its radius, therefore

$\bf ~~~~~~~~~~~~\textit{distance between 2 points}\\\\\stackrel{center}{(\stackrel{x_1}{-7}~,~\stackrel{y_1}{-1})}\qquad (\stackrel{x_2}{8}~,~\stackrel{y_2}{7})\qquad \qquad d = \sqrt{( x_2- x_1)^2 + ( y_2- y_1)^2}\\\\\\\stackrel{radius}{r}=\sqrt{[8-(-7)]^2+[7-(-1)]^2}\implies r=\sqrt{(8+7)^2+(7+1)^2}\\\\\\r=\sqrt{15^2+8^2}\implies r=\sqrt{225+64}\implies \boxed{r=17}$

and since we know that x = -15 for such a point, then

$\bf \textit{equation of a circle}\\\\ (x- h)^2+(y- k)^2= r^2\qquad center~~(\stackrel{-7}{ h},\stackrel{-1}{ k})\qquad \qquad radius=\stackrel{17}{ r}\\\\\\\[x-(-7)]^2+[y-(-1)]^2=17^2\implies (x+7)^2+(y+1)^2=289\\\\\\\stackrel{\textit{since we know x = -15}}{(-15+7)^2+(y+1)^2=289}\implies (-8)^2+\stackrel{FOIL}{(y^2+2y+1^2)}=289\\\\\\64+y^2+2y+1=289\implies y^2+2y=224\implies y^2+2y-224=0\\\\\\(y+16)(y-14)=0\implies y=\begin{cases}-16\\14\end{cases}$

since it's a circle, it touches x = -15 twice, check the picture below.

6 0

3 years ago

4 Abi is going to buy ingredients to make 65 hot chocolate drinks.

Semenov [28]

Answer:

To make 65 chocolate drinks, she needs:

12 g of chocolate powder and 5 marshmallows per drink.

Then she needs:

12g*65 = 780 grams of chocolate powder.

We know that the chocolate powder comes in jars of 250g, such that each one costs £2.99

If she buys 3 jars, she will have: 3*250g = 750g

So she will not have enough, then she needs to buy 4 jars.

Then in chocolate powder, she will pay 4 times £2.99 = £11.96

And for marshmallows, she needs:

65*5 = 325 in total.

Marshmallows come in bags of 120, then the number of packs that Abi needs to buy is:

325/120 = 2.7

That should be rounded up (because she can not buy a 0.7 of a bag)

Then she needs 3 bags, and each bag costs £1.45

Then the total cost in marshmallows is 3*£1.45 = £4.35

8 0

3 years ago

The graph of a quadratic function is shown. Check all of the following statements that are true of the function.

Fed [463]

Answer:

a < 0

The vertex is (1,2)

Step-by-step explanation:

Looking at the graph

we have a vertical parabola open downward

The leading coefficient is negative

The vertex is a maximum

The vertex is the point (1,2)

The axis of symmetry is equal to the x-coordinate of the vertex, so the axis of symmetry is x=1

The y-intercept is the point (0,1)

The function has two real solutions (zeros of the function) one positive and one negative

The positive zero of the function is greater than 2

The negative zero of the function is greater than -1

Verify each statement

case 1) a < 0

The statement is true

Because the parabola open downward

case 2) The vertex is (1,2)

The statement is true

The vertex in this problem is the maximum of the function

case 3) The axis of symmetry is y =2

The statement is false

Because the axis of symmetry is x=1

case 4) x = 2 is a zero of the function

The statement is false

Because the positive zero of the function is greater than 2

case 5) (1,2) is a minimum

The statement is false

Because the vertex in this problem is a maximum

4 0

3 years ago

I need help with question number 2.. I have a test coming up and i’m really lost

Korvikt [17]

(9a+5b-7)+(4b-2)

Add the like terms

9a+9b-9

6 0

3 years ago

Mrs.Carlyle bought a bag of peanuts for her children. When Phillip, Joy, Brent, abd Preston came home from school, they each too

Kitty [74]

Whats the question?

7 0

3 years ago