Which one weighs more a pound of bricks or a pound of cotton balls?

A rectangular prism has a length of 5 1/8 feet, a width of 7 1/2 feet, and a height of 2 feet. What is the volume of the prism?

maksim [4K]

For this case we have that by definition, the volume of a rectangular prism is given by:

$V = A_ {b} * h$

Where:

$A_ {b}:$ It is the area of the base

h: It's the height

According to the data we have:

$length = 5 \frac {1} {8} = \frac {8 * 5 + 1} {8} = \frac {41} {8}$

$width = 7 \frac {1} {2} = \frac {2 * 7 + 1} {2} = \frac {15} {2}$

Then:

$A_ {b} = \frac {41} {8} * \frac {15} {2} = \frac {615} {16}$

Thus, the volume is:

$V = \frac {615} {16} * 2 = \frac {1230} {16} = 76.875$

Answer:

$76.875 \ ft ^ 3$

6 0

2 years ago

IQ scores on the WAIS test approximate a normal curve with a mean of 100 and a standard deviation of 15. What IQ score is identi

riadik2000 [5.3K]

Answer:

IQ scores of at least 130.81 are identified with the upper 2%.

Step-by-step explanation:

Normal Probability Distribution:

Problems of normal distributions can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the z-score 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 p-value, we get the probability that the value of the measure is greater than X.

Mean of 100 and a standard deviation of 15.

This means that $\mu = 100, \sigma = 15$

What IQ score is identified with the upper 2%?

IQ scores of at least the 100 - 2 = 98th percentile, which is X when Z has a p-value of 0.98, so X when Z = 2.054.

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

$2.054 = \frac{X - 100}{15}$

$X - 100 = 15*2.054$

$X = 130.81$

IQ scores of at least 130.81 are identified with the upper 2%.

7 0

2 years ago

Answer the following for each letter true or false.

Fittoniya [83]

A. False
B. True
C. False
D. True

6 0

2 years ago

6. Two observers, 7220 feet apart, observe a balloonist flying overhead between them. Their measures of the

MaRussiya [10]

Answer:

The ballonist is at a height of 3579.91 ft above the ground at 3:30pm.

Step-by-step explanation:

Let's call:

h the height of the ballonist above the ground,

a the distance between the two observers,

$a_1$ the horizontal distance between the first observer and the ballonist

$a_2$ the horizontal distance between the second observer and the ballonist

$\alpha _1$ and $\alpha _2$ the angles of elevation meassured by each observer

S the area of the triangle formed with the observers and the ballonist

So, the area of a triangle is the length of its base times its height.

$S=a*h$ (equation 1)

but we can divide the triangle in two right triangles using the height line. So the total area will be equal to the addition of each individual area.

$S=S_1+S_2$ (equation 2)

$S_1=a_1*h$

But we can write $S_1$ in terms of $\alpha _1$ , like this:

$\tan(\alpha _1)=\frac{h}{a_1} \\a_1=\frac{h}{\tan(\alpha _1)} \\S_1=\frac{h^{2} }{\tan(\alpha _1)}$

And for $S_2$ will be the same:

$S_2=\frac{h^{2} }{\tan(\alpha _2)}$

Replacing in the equation 2:

$S=\frac{h^{2} }{\tan(\alpha _1)}+\frac{h^{2} }{\tan(\alpha _2)}\\S=h^{2}*(\frac{1 }{\tan(\alpha _1)}+\frac{1}{\tan(\alpha _2)})$

And replacing in the equation 1:

$h^{2}*(\frac{1 }{\tan(\alpha _1)}+\frac{1}{\tan(\alpha _2)})=a*h\\h=\frac{a}{(\frac{1 }{\tan(\alpha _1)}+\frac{1}{\tan(\alpha _2)})}$

So, we can replace all the known data in the last equation:

$h=\frac{a}{(\frac{1 }{\tan(\alpha _1)}+\frac{1}{\tan(\alpha _2)})}\\h=\frac{7220 ft}{(\frac{1 }{\tan(35.6)}+\frac{1}{\tan(58.2)})}\\h=3579,91 ft$

Then, the ballonist is at a height of 3579.91 ft above the ground at 3:30pm.

6 0

2 years ago

A farmer grows vegetables on a rectangular plot of land. The length of the plot is labeled in the diagram below. If the perimete

gavmur [86]

Answer:

Step-by-step explanation:

solve the question then divide

4 0

3 years ago