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2 years ago

Please help me i'll mark u as brainly if u give me the correct answers

Mathematics

2 answers:

jarptica [38.1K]2 years ago

8 0

Answer:

49π cm²

Step-by-step explanation:

Diameter (d) = 14 cm

Radius (r) = d/2 = 14/2 = 7 cm

Area of a circle

= πr²

= π × (7)²

= 49π cm²

Hope it helps ⚜

Aliun [14]2 years ago

5 0

Information provided with us :

Diameter of the given circle is 14 cm.

What we have to calculate :

Area of that circle?

Performing Calculations :

Here we would be first calculating the radius of the given circle. As we know that radius of the circle is calculated by the formula,

r = d / 2

Putting the values,

=> r = 14 / 2

=> r = 7

Therefore, radius is of 7 cm.

Now, heading up to calculate the area of circle.

Formula,

A = πr²

Putting the values in the formula,

=> A = 22/7 (7)²

=> A = (22/7) × 7 × 7

=> A = 22 × 7 × 7 / 7

=> A = 22 × 49 / 7

=> A = 22 × 7

=> A = 154 cm²

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Six divided by fivehundredsevenysik

ELEN [110]

I think you mean six-hundred and seventy six.

6 ÷ 576 = 0.010416

or 0.0104166667

8 0

3 years ago

A teacher was interested in knowing the amount of physical activity that his students were engaged in daily. He randomly sampled

klasskru [66]

Answer:

The standard error of the mean is 4.5.

Step-by-step explanation:

As we don't know the standard deviation of the population, we can estimate the standard error of the mean from the standard deviation of the sample as:

$\sigma_{\bar{x}}\approx\frac{s}{\sqrt{n}}$

The sample is [30mins, 40 mins, 60 mins, 80 mins, 20 mins, 85 mins]. The size of the sample is n=6.

The mean of the sample is:

$\bar{x}=\frac{1}n} \sum x_i =\frac{30+40+60+80+20+85}{6}=52.5$

The standard deviation of the sample is calculated as:

$s=\sqrt{\frac{1}{n-1}\sum (x_i-\bar x)^2} \\\\ s=\sqrt{\frac{1}{5}\cdot ((30-52.5)^2+(40-52.5)^2+(60-52.5)^2+(80-52.5)^2+(20-52.5)^2+(85-52.5)^2}\\\\s=\sqrt{\frac{1}{5} *3587.5}=\sqrt{717.5}=26.8$