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3 years ago

I need help with this pleasee

Mathematics

1 answer:

zhenek [66]3 years ago

7 0

Answer:

7.1×10^3kg

Step-by-step explanation:

15000-7900=7100

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AD=3, BD=5, AE=4. Find CE

EastWind [94]

Answer:

6.6

Step-by-step explanation:

Triangles ADE and ABC are similar.

Therefore,

AD/AB=AE/AC

3/8=4/AC

3AC=32

AC=10.6(3 s.f)

CE=10.6-4=6.6

5 0

3 years ago

In △XYZ , XZ=9 , YZ=4 , and XY=7 .

Mamont248 [21]

Answer:

$A=6\sqrt{5}\ units^2$

Step-by-step explanation:

we know that

Heron's Formula is a method for calculating the area of a triangle when you know the lengths of all three sides.

$A=\sqrt{s(s-a)(s-b)(s-c)}$

where

a, b and c are the length sides of triangle

s is the semi-perimeter of triangle

we have

$a=9\ units,b=4\ units,c=7\ units$

Find the semi-perimeter s

$s=\frac{9+4+7}{2}=10\ units$

Find the area of triangle

$A=\sqrt{10(10-9)(10-4)(10-7)}$

$A=\sqrt{10(1)(6)(3)}$

$A=\sqrt{180}\ units^2$

Simplify

$A=6\sqrt{5}\ units^2$

8 0

3 years ago

Use the pic for more info will mark brainlest

Lelechka [254]

Answe7.5 i think

Step-by-step explanation:

4 0

3 years ago

A manager records the repair cost for 4 randomly selected stereos. A sample mean of $82.64 and standard deviation of $14.32 are

zysi [14]

Answer:

CI = (70.861 , 94.418)

Step-by-step explanation:

In order to determine the 90% confidence interval you use the following formula (for a population approximately normal):

$CI=(\overline{x}-Z_{\alpha/2}\frac{\sigma}{\sqrt{n}},\overline{x}+Z_{\alpha/2}\frac{\sigma}{\sqrt{n}})$ (1)

$\overline{x}$ : mean = 82.64

σ: standard deviation = 14.32

n: sample = 4

α: tail area = 1 - 0.9 = 0.1

Z_α/2 = Z_0.05: Z factor = 1.645

You replace these values and you obtain:

$Z_{0.05}(\frac{14.32}{\sqrt{4}})=(1.645)(\frac{14.32}{\sqrt{4}})=11.778$

The confidence interval will be:

$CI=(82.64-11.778,82.64+11.778)=(70.861,94.418)$

The 90% confidence interval is (70.861 , 94.418)

6 0

4 years ago

4x2 + 8x – 9 = 0 complet the square

lisov135 [29]

The answer is 1/8. That is the answer for this question.

6 0

3 years ago