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3 years ago

What is the surface area of the faces of the pyramid?

Mathematics

1 answer:

Alekssandra [29.7K]3 years ago

8 0

The area of a triangle is (base*height)/2
Therefore: 12*10=120/2=60. Since there are three triangles then you multiply 60 by three. 60*3=180
Since the triangle in the middle is equilateral the height is 10. (10*10)/2=50
180+50=230
The answer is 230 inches²

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The interior ages of a triangle have measure

Nina [5.8K]

Answer:

See below in bold.

Step-by-step explanation:

1. The 3 angles in a triangle add up to 180 degrees.

So x = 180 - (55 + 25)

= 180 - 80

= 100 degrees.

2. The 4 angles in a quadrilateral add up to 360 degrees,, so

3x + 127 + 54 + 119 = 360

3x + 300 = 360

3x = 360 - 300

3x = 60

x = 20 degrees.

3. Exterior angle

= 94 + 42

= 136 degrees.

3 0

3 years ago

Read 2 more answers

Steve is painting the ceiling of a room. the ceiling is in the shape of a rectangle. he has enough paint to cover 198 square fee

Katena32 [7]

Answer:

Width = 9ft.

Length=22ft.

Step-by-step explanation:

4 0

1 year ago

Select from the following choices those graphs that represent only a dilation applied to this polygon with a scale factor great

romanna [79]

Answer:

B and C

Step-by-step explanation:

Required

Select graphs that are dilated by a scale factor greater than 1

For graph A:

Graph A is smaller than the original graph. This indicates dilation with a scale factor less than 1

For graph B:

Graph B is bigger than the original graph and is dilated over (0,0). This indicates dilation with a scale factor greater than 1

For graph C:

Graph C is bigger than the original graph; however, it is not dilated over (0,0). This indicates dilation with a scale factor greater than 1

For graph D:

Graph D is bigger than the original graph; however, it is not only dilated but also flipped over (i.e. rotated).

<em>Hence, b and c is true</em>

5 0

2 years ago

If you were moving at 14mph for 8 miles, how long would it take you to travel the 8 miles?

Rainbow [258]

Answer

34 minutes

Step-by-step explanation:

3 0

2 years ago

Let the following sample of 8 observations be drawn from a normal population with unknown mean and standard deviation:

Vikentia [17]

Answer:

$\= x = 18.5$ , $\sigma = 5.15$

$15.505 < \mu < 21.495$

$14.93 < \mu < 22.069$

Step-by-step explanation:

From the question we are are told that

The sample data is 21, 14, 13, 24, 17, 22, 25, 12

The sample size is n = 8

Generally the ample mean is evaluated as

$\= x = \frac{\sum x }{n}$

$\= x = \frac{ 21 + 14 + 13 + 24 + 17 + 22+ 25 + 12 }{8}$

$\= x = 18.5$

Generally the standard deviation is mathematically evaluated as

$\sigma = \sqrt{\frac{\sum (x- \=x )^2}{n}}$

$\sigma = \sqrt{\frac{\sum ((21 - 18.5)^2 + (14-18.5)^2+ (13-18.5)^2+ (24-18.5)^2+ (17-18.5)^2+ (22-18.5)^2+ (25-18.5)^2+ (12 -18.5)^2 )}{8}}$

$\sigma = 5.15$

considering part b

Given that the confidence level is 90% then the significance level is evaluated as

$\alpha = 100-90$

$\alpha = 10\%$

$\alpha = 0.10$

Next we obtain the critical value of $\frac{ \alpha }{2}$ from the normal distribution table the value is

$Z_{\frac{ \alpha }{2} } = 1.645$

The margin of error is mathematically represented as

$E = Z_{\frac{ \alpha }{2} } * \frac{\sigma }{\sqrt{n} }$

=> $E =1.645 * \frac{5.15 }{\sqrt{8} }$

=> $E = 2.995$

The 90% confidence interval is evaluated as

$\= x - E < \mu < \= x + E$

substituting values

$18.5 - 2.995 < \mu < 18.5 + 2.995$

$15.505 < \mu < 21.495$

considering part c

Given that the confidence level is 95% then the significance level is evaluated as

$\alpha = 100-95$

$\alpha = 5\%$

$\alpha = 0.05$

Next we obtain the critical value of $\frac{ \alpha }{2}$ from the normal distribution table the value is

$Z_{\frac{ \alpha }{2} } = 1.96$

The margin of error is mathematically represented as

$E = Z_{\frac{ \alpha }{2} } * \frac{\sigma }{\sqrt{n} }$

=> $E =1.96 * \frac{5.15 }{\sqrt{8} }$

=> $E = 3.569$

The 95% confidence interval is evaluated as

$\= x - E < \mu < \= x + E$

substituting values

$18.5 - 3.569 < \mu < 18.5 + 3.569$

$14.93 < \mu < 22.069$

8 0

2 years ago