$Area_{(circle)}=\pi r^2\qquad and\qquad r=\dfrac{diameter}{2}\\\\\\\implies Area_{(circle)}=\pi \bigg(\dfrac{diameter}{2}\bigg)^2\\\\\\\text{It is given that the diameter = 26:}\\A=\pi\bigg(\dfrac{26}{2}\bigg)^2\\\\\\.\quad =\pi \cdot 13^2\\\\\\.\quad =169\pi\\\\\\.\quad =\large\boxed{530.66}$

3 0

4 years ago

7th grade work help please<br> will give brainliest:)

Montano1993 [528]

Answer: 67.27

Step-by-step explanation:

7.1 x 7.1 for the square = 50.41

7.1 divided by 2 = 3.55

3.55 x 4.75= 16.86

Normally here you would divide by 2, but you don’t need two because there is 2 triangles that are the same

Add the 50.41 and the 16.86 and you have your answer!

4 0

3 years ago

In a sample of 1000 cases, the mean of a certain test is 14 and the standard deviation is 2.5. Assume the distribution to be nor

Maslowich

Answer:

The top 20% of the students will score at least 2.1 points above the mean.

Step-by-step explanation:

When the distribution is normal, we use the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

The mean of a certain test is 14 and the standard deviation is 2.5.

This means that $\mu = 14, \sigma = 2.5$