1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
svlad2 [7]
3 years ago
13

Help me with this question please!

Mathematics
1 answer:
Amiraneli [1.4K]3 years ago
7 0

Answer:

84 in²

Step-by-step explanation:

12+9=21

21x0.5=10.5

10.5x8=84

You might be interested in
• A researcher claims that less than 40% of U.S. cell phone owners use their phone for most of their online browsing. In a rando
antiseptic1488 [7]

Answer:

We failed to reject H₀

Z > -1.645

-1.84 > -1.645

We failed to reject H₀

p > α

0.03 > 0.01

We do not have significant evidence at a 1% significance level to claim that less than 40% of U.S. cell phone owners use their phones for most of their online browsing.

Step-by-step explanation:

Set up hypotheses:

Null hypotheses = H₀: p = 0.40

Alternate hypotheses = H₁: p < 0.40

Determine the level of significance and Z-score:

Given level of significance = 1% = 0.01

Since it is a lower tailed test,

Z-score = -2.33 (lower tailed)

Determine type of test:

Since the alternate hypothesis states that less than 40% of U.S. cell phone owners use their phone for most of their online browsing, therefore we will use a lower tailed test.

Select the test statistic:  

Since the sample size is quite large (n > 30) therefore, we will use Z-distribution.

Set up decision rule:

Since it is a lower tailed test, using a Z statistic at a significance level of 1%

We Reject H₀ if Z < -1.645

We Reject H₀ if p ≤ α

Compute the test statistic:

$ Z =  \frac{\hat{p} - p}{ \sqrt{\frac{p(1-p)}{n} }}  $

$ Z =  \frac{0.31 - 0.40}{ \sqrt{\frac{0.40(1-0.40)}{100} }}  $

$ Z =  \frac{- 0.09}{ 0.048989 }  $

Z = - 1.84

From the z-table, the p-value corresponding to the test statistic -1.84 is

p = 0.03288

Conclusion:

We failed to reject H₀

Z > -1.645

-1.84 > -1.645

We failed to reject H₀

p >  α

0.03 > 0.01

We do not have significant evidence at a 1% significance level to claim that less than 40% of U.S. cell phone owners use their phones for most of their online browsing.

8 0
3 years ago
In a right triangle ABC, CD is an altitude, such that AD=BC. Find AC, if AB=3 cm, and CD= 2 cm.
konstantin123 [22]

Consider right triangle ΔABC with legs AC and BC and hypotenuse AB. Draw the altitude CD.

1. Theorem: The length of each leg of a right triangle is the geometric mean of the length of the hypotenuse and the length of the segment of the hypotenuse adjacent to that leg.

According to this theorem,

BC^2=BD\cdot AB.

Let BC=x cm, then AD=BC=x cm and BD=AB-AD=3-x cm. Then

x^2=(3-x)\cdot 3,\\ \\x^2=9-3x,\\ \\x^2+3x-9=0,\\ \\D=3^2-4\cdot (-9)=9+36=45,\\ \\\sqrt{D}=\sqrt{45}=3\sqrt{5},\\ \\x_1=\dfrac{-3-3\sqrt{5} }{2}0.

Take positive value x. You get

AD=BC=\dfrac{-3+3\sqrt{5} }{2}\ cm.

2. According to the previous theorem,

AC^2=AD\cdot AB.

Then

AC^2=\dfrac{-3+3\sqrt{5} }{2}\cdot 3=\dfrac{-9+9\sqrt{5} }{2},\\ \\AC=\sqrt{\dfrac{-9+9\sqrt{5} }{2}}\ cm.

Answer: AC=\sqrt{\dfrac{-9+9\sqrt{5} }{2}}\ cm.

This solution doesn't need CD=2 cm. Note that if AB=3cm and CD=2cm, then

CD^2=AD\cdot DB,\\ \\2^2=AD\cdot (3-AD),\\ \\AD^2-3AD+4=0,\\ \\D

This means that you cannot find solutions of this equation. Then CD≠2 cm.

8 0
3 years ago
Read 2 more answers
Whats the overall homework score ?
Pavel [41]

Answer:

the answer is h 86.8 first you gotta take all the numbers then drop the two lowest  then you multiply the ones you hsve left then divide it by the number of grsdes there is

8 0
3 years ago
Which is the longest 2 km 25m 2500 cm or 3000 mm
MAVERICK [17]
2km=2 kilometer
kilo=1000 so 2 km=2000m

25m

2500cm
cm=centimeter=1/100 of a meter
so
2500cm=25m


mm=milimeter=1/1000 meter
so
3000mm=3m

so the longets is obviously 2000m or 2km
6 0
3 years ago
Read 2 more answers
There are 10 girls and 8 boys in Mr Augellis class. If 5 more girls and 5 more boys join the class, will the ratio of girls to b
zimovet [89]
Yes they will stay the same
8 0
3 years ago
Other questions:
  • Divide 33 into two groups so the ratio is 4 to 7
    14·1 answer
  • Find the value of x.
    6·1 answer
  • What is the percent of change from 240 to 480?
    12·1 answer
  • I really need the answers for these I don't understand this
    9·1 answer
  • Which expression should you simplify to find the 90% confidence interval,
    7·1 answer
  • Dwayne's garden is triangle-shaped with two equal sides and a third side that is 4 ft more than the length of an equal side. If
    7·2 answers
  • What is the length of side EF in the triangle? Please give a step by step explanation, I'm having lots of trouble finding the so
    10·1 answer
  • Plz I need help with this test that I have due today!!!!!
    6·1 answer
  • Help a friend out plz
    11·2 answers
  • Tính (x+1)^3-x(x-2)^2-1
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!