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3 years ago

What is the surface of a cube with the side lenght of 9cm

Mathematics

1 answer:

marissa [1.9K]3 years ago

5 0

<span>The total surface area is SA = 6 </span>× $a^{2}$ ;
SA = 6 × $9^{2}$ = 6 × 81 = 486 $cm^{2}$ ;

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2.The diagonals of a rhombus are in the ratio 5:12. If its perimeter is 104 CM, findthe lengths of the sides and the diagonals.

coldgirl [10]

Answer:

Lenghts of the sides: $26\ cm$

Lenghts of the diagonals: $48\ cm$ and $20\ cm$

Step-by-step explanation:

Look at the rhombus ABCD shown attached, where AC and BD de diagonals of the rhombus.

The sides of a rhombus have equal lenght. Then, since the perimeter of this one is 104 centimeters, you can find the lenght of each side as following:

$AB=BC=CD=DA=\frac{104\ cm}{4}= 26\ cm$

You know that the diagonals are in the ratio $5:12$

Then, let the diagonal AC be:

$AC=12x$

This means that AE is:

$AE=\frac{12x}{2}=6x$

And let the diagonal BD be:

$BD=5x$

So BE is:

$BE=\frac{5x}{2}=2.5x$

Since the diagonals of a rhombus are perpendicular to each other, four right triangles are formed, so you can use the Pythagorean Theorem:

$a^2=b^2+c^2$

Where "a" is the hypotenuse and "b" and "c" are the legs.

In this case, you can choose the triangle ABE. Then:

$a=AB=26\\b=AE=6x\\c=BE=2.5x$

Substituting values and solving for "x", you get:

$26^2=(6x)^2+(2.5x)^2\\\\676=36x^2+6.25x^2\\\\\sqrt{\frac{676}{42.25}}=x\\\\x=4$

Therefore, the lenghts of the diagonals are:

$AC=12(4)\ cm=48\ cm$

$BD=5(4)\ cm=20\ cm$

8 0

3 years ago

Help with math, please!

Alinara [238K]

It is C. A cube! Good luck!

8 0

3 years ago

Read 2 more answers

Consider circle y with radius 4 m and m angle xyz=80 degrees

elixir [45]

The answer is a.5.6cm

6 0

3 years ago

The newest invention of the 6.431x staff is a three-sided die. On any roll of this die, the result is 1 with probability 1/2, 2

Gwar [14]

Answer:

<h2>The answer is 0.23(approx).</h2>

Step-by-step explanation:

The given die is a three sided die, hence, there are only three possibilities of getting the outcomes.

We need to find the probability of getting exactly 3s as the result.

From the sequence of 6 independent rolls, 2 rolls can be chosen in $^6C_2 = \frac{6!}{2!\times4!} = \frac{30}{2} = 15$ ways.

The probability of getting two 3 as outcome is $\frac{1}{4} \times\frac{1}{4} = \frac{1}{16}$ .

In the rest of the 4 sequences, will not be any 3 as outcome.

Probability of not getting a outcome rather than 3 is $1 - \frac{1}{4} = \frac{3}{4}$ .

Hence, the required probability is $15\times\frac{1}{16}(\frac{3}{4})^4 = \frac{1215}{4096}$ ≅0.2966 or, 0.23.

4 0

3 years ago

Ch lists the steps in the correct order to find the median of this data set?

anygoal [31]

Answer:

Put the numbers in order
Cross off the high/low pairs
Add the leftover numbers
Divide the sum by 2

=================================================

Explanation:

The numbers sort to this

16, 18, 23, 24, 29, 30

Cross off the outer most values 16 and 30 to end up with this smaller set

18, 23, 24, 29

Then repeat to get this smaller set

23,24

We add up these numbers and divide the sum by 2

(23+24)/2 = 47/2 = 23.5

The median is 23.5

The last steps of adding and dividing by 2 only works if we have an even number of values in the original set.

3 0

2 years ago