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3 years ago

Help me pleaaaaaseeee

Mathematics

1 answer:

Archy [21]3 years ago

7 0

A = 28.356 ≈ 28.4

Here, we use law of sines, which says that sina / A = sinb / B. We know that b = 130 degrees, B = 10cm, and A = 6.2cm. Using algebra, we solve sina / 6.2 = sin130 / 10 to get a final answer.

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John wants to see the formulas he has used in his spreadsheet but he does not want to see the results of the formulas. How does

vova2212 [387]

In order to see the formulas that you used in a spreadsheet, but doesn't want to see the results of the formulas, then just click on Show Formulas. That can be done by clicking the cell and click, show formula. Letter A.

5 0

3 years ago

Prove that the triangle EDF is isosceles. Give reasons for your answer.

Gekata [30.6K]

Answer:

$\triangle EDF$ is isosceles.

Step-by-step explanation:

Please have a look at the attached figure.

We are given the following things:

$\angle EDF = y$

$\text{External }\angle DFG = 90 +\dfrac{y}{2}$

Let us try to find out $\angle E$ and $\angle DFE$ . After that we will compare them.

Finding  $\angle DFE$ :

Side EG is a straight line so $\angle GFE = 180$

$\angle GFE$ is sum of internal $\angle DFE$ and external $\angle DFG$

$\angle GFE = 180 = \angle DFE + \angle DFG\\\Rightarrow 180 = \angle DFE + (90+\dfrac{y}{2})\\\Rightarrow \angle DFE = 180 - 90 - \dfrac{y}{2}\\\Rightarrow \angle DFE = 90 - \dfrac{y}{2} ....... (1)$

Finding  $\angle E$ :

Property of external angle: External angle in a triangle is equal to the sum of two opposite internal angles of a triangle.

i.e. external $\angle DFG$ = $\angle E + \angle EDF$

$\Rightarrow 90+\dfrac{y}{2} = \angle E + y\\\Rightarrow \angle E = 90+\dfrac{y}{2} -y\\\Rightarrow \angle E = 90-\dfrac{y}{2} ....... (2)$

Comparing equations (1) and (2):

It can be clearly seen that:

$\angle DFE = \angle E =90-\dfrac{y}{2}$

The two angles of $\triangle EDF$ are equal hence $\triangle EDF$ is isosceles.

8 0

3 years ago

A and B can fill a cistern in 4 hours. A and C can fill

kirill [66]

Answer:

20 hours

Step-by-step explanation:

We can work easier if we think in terms of an hour

the first equation that we can write is

A + B = 1/4 (its meaning is that in an hour A and B fill 1/4 of the cistern)

the second equation we can write is

A + C = 1/5 (its meaning is that in an hour A and C fill 1/5 of the cistern)

the third equation that we can write is

B = 2C (its meaning is that in an hour B fill 2 times C the cistern)

now we can substitute the value of B in the first two equations

A + 2C = 1/4

A + C = 1/5

A = 1/5 - C

1/5 - C + 2C = 1/4

C = 1/4 -1/5

C = (5-4)/20

C = 1/20 (this means that in an hour C will fill 1/20 of the cistern, so it takes 20 hours to fill the entire cistern)

A = 1/5 - 1/20

A = (4-1)/20 = 3/20

B = 1/20 *2 = 1/10

4 0

3 years ago

The height of a triangle is 4 sqrt 3 . What is the perimeter of the equatorial triangle?

Karo-lina-s [1.5K]

The perimeter of the equatorial triangle is 24 units

<h3>Solution:</h3>

Given that,

An equilateral triangle has an height equal to $4 \sqrt{3}$

The triangle is shown below

From Triangle ABC in the shown figure AD $=4 \sqrt{3}$

Let the sides of the equilateral triangle be ‘a’

AB = BC = a

Since, it is an equilateral triangle we get,

BD = DC = a ÷ 2

Now, using Pythagoras Theorem in Triangle ABD,

The Pythagorean theorem is this: In a right triangle, the sum of the squares of the lengths of the two legs is equal to the square of the length of the hypotenuse.

$\mathrm{AB}^{2}=\mathrm{BD}^{2}+\mathrm{AD}^{2}$

$\begin{array}{l}{a^{2}=\left(\frac{a}{2}\right)^{2}+(4 \sqrt{3})^{2}} \\\\ {a^{2}-\left(\frac{a}{2}\right)^{2}=(4 \sqrt{3})^{2}}\end{array}$

$\frac{4 a^{2}-a^{2}}{4}=16 \times 3$

$\begin{array}{l}{\frac{3 a^{2}}{4}=16 \times 3} \\\\ {3 a^{2}=192} \\\\ {a^{2}=192 \div 3=64}\end{array}$

a = 8

Hence, the three sides of the triangle are 8 units each

In equilateral traingle, length of all three sides of triangle are equal

So, Perimeter = 3 $\times$ (Length of each side of triangle)

Perimeter = 3 $\times$ 8 = 24

Thus the perimeter of the equatorial triangle is 24 units

7 0

4 years ago

Can someone help me? Plzzzzz :c I need it for tmw

lys-0071 [83]

$x-cost\ of\ DVD\\y-cost\ of\ video\ game\\\\ \left \{ {{3x+14y=203\ \ \ } \atop {11x+11y=220\ \ } \right. \\\\ From\ first\ second:\\11x=220-11y\ \ \ \ |:11\\x=20-y\\\\Substitute\ to\ first:\\3(20-y)+14y=203\\60-3y+14y=203\\-3y+14y=203-60\\11y=143\ \ \ \ |:11\\y=13\\\\x=20-13=7\\\\ \left \{ {{y=13} \atop {x=7}} \right.$

5 0

3 years ago

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Help me pleaaaaaseeee​

Help me pleaaaaaseeee