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3 years ago

Types of circle geometry concepts

Mathematics

1 answer:

SOVA2 [1]3 years ago

3 0

Answer:

Circle basic concepts: Chords, arcs, tangents, cyclic quadrilateral, angle subtended by a chord and secant of a circle with examples and exercise. Contents are, Definition of a circle.

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The height of water shooting from a fountain is modeled by the function f(x) = −0.2x2 − 2.8x − 5.4 where x is the distance from

balandron [24]

Start by setting the function equal to 0 and then moving the -5.4 over to the other side of the equals sign. $-.2 x^{2} -2.8x=5.4$ . The first rule for completing the square is that the leading coefficient be a +1. Ours is a -.2. So we need to factor it out. $-.2( x^{2} +14x)=5.4$ . Now we will take half the linear term, square it, and add it to both sides. Our linear term is 14. Half of 14 is 7, and 7 squared is 49. So we add 49 in to the left side just fine, but we cannot forget about that -.2 hanging around out front as a multiplier. What we have actually "added" in is -.2*49 which is -9.8. Now here's what we have after all that: $-.2( x^{2} +14x+49)=5.4-9.8$ . In that process, we have created a perfect square binomial on the left. Along with expressing that binomial we will do the math on the right: $-.2(x+7) ^{2} =-4.4$ . Now we will move the -4.4 back over by addition, and it will then be apparent as to what our vertex is. The y coordinate of the vertex will give us the max height of the water. $-.2(x+7) +4.4=y$ . As you can see, our work matches choice C from above.

4 0

2 years ago

PLAYGROUND There are 87 children at a playground. There are 23 more boys than girls. How many of each are at the playground?

UNO [17]

Answer:

G=32 B=55

Step-by-step explanation:

55+32=87

I know this answer is right bc I got it right on my ws.

3 0

3 years ago

The summer monsoon brings 80% of India's rainfall and is essential for the country's agriculture.

Natasha_Volkova [10]

Answer:

Step 1. Between 688 and 1016mm. Step 2. Less than 688mm.

Step-by-step explanation:

The 68-95-99.7 rule roughly states that in a normal distribution 68%, 95% and 99.7% of the values lie within one, two and three standard deviation(s) around the mean. The z-scores represent values from the mean in a standard normal distribution, and they are transformed values from which we can obtain any probability for any normal distribution. This transformation is as follows:

$\\ z = \frac{x - \mu}{\sigma}$ (1)

$\\ \mu\;is\;the\;population\;mean$

$\\ \sigma\;is\;the\;population\;standard\;deviation$

And x is any value which can be transformed to a z-value.

Then, z = 1 and z = -1 represent values for one standard deviation above and below the mean, respectively; values of z = 2 and z =-2, represent values for two standard deviations above and below the mean, respectively and so on.

Because of the 68-95-99.7 rule, we know that approximately 95% of the values for a normal distribution lie between z = -2 and z = 2, that is, two standard deviations below and above the mean as remarked before.

<h3>Step 1: Between what values do the monsoon rains fall in 95% of all years?</h3>

Having all this information above and using equation (1):

$\\ z = \frac{x - \mu}{\sigma}$

For z = -2:

$\\ -2 = \frac{x - 852}{82}$

$\\ -2*82 + 852 = x$

$\\ x_{below} = 688mm$

For z = 2:

$\\ 2 = \frac{x - 852}{82}$

$\\ 2*82 = x - 852$

$\\ 2*82 + 852 = x$

$\\ x_{above} = 1016mm$

Thus, the values for the monsoon rains fall between 688mm and 1016mm for approximately 95% of all years.

<h3>Step 2: How small are the monsoon rains in the driest 2.5% of all years?</h3>

The driest of all years means those with small monsoon rains compare to those with high values for precipitations. The smallest values are below the mean and at the left part of the normal distribution.

As you can see, in the previous question we found that about 95% of the values are between 688mm and 1016mm. The rest of the values represent 5% of the total area of the normal distribution. But, since the normal distribution is symmetrical, one half of the 5% (2.5%) of the remaining values are below the mean, and the other half of the 5% (2.5%) of the remaining values are above the mean. Those represent the smallest 2.5% and the greatest 2.5% values for the normally distributed data corresponding to the monsoon rains.

As a consequence, the value x for the smallest 2.5% of the data is precisely the same at z = -2 (a distance of two standard deviations from the mean), since the symmetry of the normal distribution permits that from the remaining 5%, half of them lie below the mean and the other half above the mean (as we explained in the previous paragraph). We already know that this value is x = 688mm and the smallest monsoons rains of all year are less than this value of x = 688mm, representing the smallest 2.5% of values of the normally distributed data.

The graph below shows these values. The shaded area are 95% of the values, and below 688mm lie the 2.5% of the smallest values.