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Tresset [83]
3 years ago
8

A 10 meter ladder is leaned up against a building. If

Mathematics
1 answer:
kirill115 [55]3 years ago
5 0

Answer:

8.7

Step-by-step explanation:

Use trigonometry. The ladder and the building form a right triangle with the ground. You are given the length of the hypotenuse and the base angle. You use sine since we are trying to figure out the opposite side from the angle and we have the hypotenuse length. Sin = opposite/hypotenuse. So in this case, sin 60°= x/10. We solve for x by multiplying both sides by 10. Now x= sin 60° (10) = (0.8660)(10) = 8.7 m.

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To which subset of the real numbers does -18 not belong?
Finger [1]

A.

-18 doesnt belong to irrational

4 0
3 years ago
A​ 9-year-old girl did a science fair experiment in which she tested professional touch therapists to see if they could sense he
Orlov [11]

Answer:

We conclude that the the touch therapists does not use a method equivalent to random guesses.

Yes, the results suggest that touch therapists are​ effective.

Step-by-step explanation:

We are given that in a 9-year-old girl did a science fair experiment in which she tested professional touch therapists to see if they could sense her energy field.

Among 264264 ​trials, the touch therapists were correct 105105 times.

<u><em>Let p = proportion that touch therapists uses a random guess method.</em></u>

Here, random guess means; p = 50%

So, Null Hypothesis, H_0 : p = 50%     {means that the touch therapists use a method equivalent to random guesses}

Alternate Hypothesis, H_A : p \neq 50%     {means that the touch therapists does not use a method equivalent to random guesses}

The test statistics that would be used here <u>One-sample z proportion statistics</u>;

                         T.S. =  \frac{\hat p-p}{\sqrt{\frac{\hat p(1-\hat p)}{n} } }  ~ N(0,1)

where, \hat p  = sample proportion of touch therapists were correct = \frac{105}{264} = 0.39

            n = sample of trials = 264

So, <em><u>test statistics</u></em>  =  \frac{\frac{105}{264} -0.50}{\sqrt{\frac{\frac{105}{264}(1-\frac{105}{264})}{264} } }  

                                =  -3.395

The value of z test statistics is -3.395.

<em>Now, at 0.05 significance level the z table gives critical value of -1.96 and 1.96 for two-tailed test. Since our test statistics does not lie within the range of critical values of z, so we have sufficient evidence to reject our null hypothesis as it will in the rejection region due to which </em><u><em>we reject our null hypothesis</em></u><em>.</em>

Therefore, we conclude that the the touch therapists does not use a method equivalent to random guesses.

Yes, the results suggest that touch therapists are​ effective.

3 0
3 years ago
The table shows the heights of 40 students in a class.
Darya [45]

Answer

A. 129.3

B. The students ages can be any number within the ranges, so having the middle number wont represent the other possible heights.

Step by step

'h' is the number between the surrounding number, the first would be 122.

You need to multiply the hight by frequency of each one,

122x7 =854

126x8=1008

130x13=1690

134x9=1206

138x3=414

Add them up = 5172

5172/40 =129.3

4 0
2 years ago
HELP ASAP PLEASE<br> List the numbers from LEAST to GREATEST <br>22/25, 8/9, and 0.8888
Digiron [165]

Answer:

I think its 22/25 , 0.8888, and then 8/9

Step-by-step explanation:

first convert them to decimals

can i get brainliest

5 0
3 years ago
Sandra is traveling 19 mph on her bicycle. After 2 hours, how far will she have traveled?
Xelga [282]

Answer:

38

Step-by-step explanation:

19

+

19

----------------------

38

3 0
3 years ago
Read 2 more answers
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