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3 years ago

13

Who is correct? Explain your reasoning. (Picture included)

1 answer:

Arada [10]3 years ago

6 0

Answer:

Gail is correct

Step-by-step explanation:

Angle 4 is congruent to <1 (vertical angles), <5 (alternate interior angles) and <8 (corresponding angles), and supplementary to the rest (e.g Angle 2 + Angle 4 = 180°)

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can someone please help me find the surface area of the pyramid with an equilateral triangle for a base

ioda

To obtain the total surface we have to calculate the surface of the 4 triangles and add up the areas (remember that the area of a triangle is (b*h)/2 , b is the base, h is the height ).

We will caculate first the area of the base triangle for that we considerer the fact that it is an equilateral triangle with sides of lenght 6 cm, now we calculate the height, I am going to draw please wait a moment

using the pythagorean theorem we have that

$\begin{gathered} h^2=6^2cm^2-3^2\operatorname{cm}=27cm^2 \\ h=\text{ }\sqrt[]{27\text{ }}cm \end{gathered}$

Then, the area of the triangle is 6*h/2 = 3h = 15.59 cm^2.

Now we calculate the area of the other 3 triangles, notice that those triangles have the same base and height so we will calculate for one of them and multiply by 3. From the image we know that the height is 15cm and the base is 6 cm so the area is 45cm^2, and 45*3 cm^2 = 135cm^2.

Finally we add up all the areas:

$135cm^2+15.59cm^2=150.59cm^2$

6 0

1 year ago

Mindy and Daisy are making necklaces using beads. Mindy uses 4 red beads for every 5 white beads. Daisy uses 6 red beads for eve

makvit [3.9K]

Answer:

Daisy

Step-by-step explanation:

Daisy:

12/4=3

3*5=15 white beads

Mindy:

12/6=2

2*7=14 white beads

7 0

3 years ago

Answer 21 & 22 for BRAINLIEST

Debora [2.8K]

I believe that 21 is d 27 over 17
I believe that 22 is d because 16 divided by 3.20 is 5
sorry if I am wrong

I hope this helps you

4 0

3 years ago

Read 2 more answers

Write down the explicit solution for each of the following: a) x’=t–sin(t); x(0)=1

Kay [80]

Answer:

a) x=(t^2)/2+cos(t), b) x=2+3e^(-2t), c) x=(1/2)sin(2t)

Step-by-step explanation:

Let's solve by separating variables:

$x'=\frac{dx}{dt}$

a) x’=t–sin(t), x(0)=1

$dx=(t-sint)dt$

Apply integral both sides:

$\int {} \, dx=\int {(t-sint)} \, dt\\\\x=\frac{t^2}{2}+cost +k$

where k is a constant due to integration. With x(0)=1, substitute:

$1=0+cos0+k\\\\1=1+k\\k=0$

Finally:

$x=\frac{t^2}{2} +cos(t)$

b) x’+2x=4; x(0)=5

$dx=(4-2x)dt\\\\\frac{dx}{4-2x}=dt \\\\\int {\frac{dx}{4-2x}}= \int {dt}\\$

Completing the integral:

$-\frac{1}{2} \int{\frac{(-2)dx}{4-2x}}= \int {dt}$

Solving the operator:

$-\frac{1}{2}ln(4-2x)=t+k$

Using algebra, it becomes explicit:

$x=2+ke^{-2t}$

With x(0)=5, substitute:

$5=2+ke^{-2(0)}=2+k(1)\\\\k=3$

Finally:

$x=2+3e^{-2t}$

c) x’’+4x=0; x(0)=0; x’(0)=1

Let $x=e^{mt}$ be the solution for the equation, then:

$x'=me^{mt}\\x''=m^{2}e^{mt}$

Substituting these equations in <em>c)</em>

$m^{2}e^{mt}+4(e^{mt})=0\\\\m^{2}+4=0\\\\m^{2}=-4\\\\m=2i$

This becomes the solution <em>m=α±βi</em> where <em>α=0</em> and <em>β=2</em>

$x=e^{\alpha t}[Asin\beta t+Bcos\beta t]\\\\x=e^{0}[Asin((2)t)+Bcos((2)t)]\\\\x=Asin((2)t)+Bcos((2)t)$

Where <em>A</em> and <em>B</em> are constants. With x(0)=0; x’(0)=1:

$x=Asin(2t)+Bcos(2t)\\\\x'=2Acos(2t)-2Bsin(2t)\\\\0=Asin(2(0))+Bcos(2(0))\\\\0=0+B(1)\\\\B=0\\\\1=2Acos(2(0))\\\\1=2A\\\\A=\frac{1}{2}$

Finally:

$x=\frac{1}{2} sin(2t)$

7 0

3 years ago

PLEASE HELP <br><br>What is the slope of this line? <br><br>a) -2 <br>b) -1/2<br>c) 1/2<br>d) 2

anyanavicka [17]

Answer:

C: 1/2

Step-by-step explanation:

Use the slope formula

5 0

3 years ago

Read 2 more answers