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Jul 30, 2017
 #7
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Jul 30, 2017
 #3
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Jul 30, 2017
 #1
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Jul 30, 2017
 #2
avatar+2442 
+1

Ok, I will assume for this problem that the 5 is labeled in inches, even though it does not say in the diagram. Yet again, I'll attempt to create a makeshift diagram like I did for you before.

 

      A                      5in                            B

      ------------------------------------------------

    /  |                                                     |  \

   /   |                                                     |    \

  /    | (2*sqrt(3))in                                 |      \

 /     |                                                     |        \

/      |                                                     |          \

--------------------------------------------------------------

D    E                                                   F           C

 

Let's remember what an altitude is; an altitude is the height that runs perpendicularly from a base to a vertex of the figure. Therefore, \(m\angle AED =90^{\circ}\). We already know that \(m\angle D=60^{\circ}\) by the given info. Of course, by the triangle sum theorem, \(m\angle DAE=(180-(90+60))^{\circ}=30^{\circ}\).

 

What does this mean? We have identified a 30-60-90 triangle in the diagram, and that is a special one! Let me explain with a diagram:
 

Source: http://study.com/cimages/multimages/16/30-60-90-example-diagram.png

 

This diagram shows the relationship between the sides and the angle measures.

 

1) The angle across 30 is x

2) The angle across 60 is \(x\sqrt{3}\)

3) The angle across the right angle is 2x.

 

This means that the ratio of the sides of a 30-60-90 triangle is \(1:\sqrt{3}:2\). Let's use this information to solve for some missing sides.

 

\(DE\sqrt{3}=AE=2\sqrt{3}\) This is the ratios of the side lengths determined above.
\(DE\sqrt{3}=2\sqrt{3}\) Divide by \(\sqrt{3}\) on both sides.
\(DE=2\)  
   

 

We have determined the length of DE, 2. Now, let's determine the length of the hypotenuse of \(\triangle ADE\) by using the ratio of the side lengths.

 

\(2DE=AD\) Substitute the value that we calculated for DE, 2.
\(AD=2*2=4\)  
   

 

Note that the same relationship occurs for the other triangle, \(\triangle BFC\), so \(FC=2\) and \(CB=4\). There is only one length we haven't determined the length of. It is \(EF\).

 

The length of this is right in front of us!  \(AB=EF=5\). Now, add all of these together!

 

\(P=(5+4+2+5+2+4)in\) Add these lengths together to get the final perimeter of the trapezoid, in inches. 
\(P=22in\)  
   

 

Bam! Done!

Jul 30, 2017
 #1
avatar+4614 
0
Jul 30, 2017
 #1
avatar+2442 
0

If you are going to list decimals, I would highly advise separating them with commas, as opposed with a numbered list. The decimals are confusing to read. If you want to use a numbered list still, I would do what I did below.

 

This is how I would revise your question:
 

Write each decimal as a fraction in simplest form.

 

1) 0.222

2) 0.1515

3) .0242424

4) 0.5555

5) -0.124124124

 

This is what I perceive the intended decimals to be, but I am not entirely sure, so correct me if I am wrong. 

 

I will start with the first decimal, 0.222.

 

\(0.222\) First, identify what place the decimal extends until (in this case, it extends to the thousandths place) and set it equal to a fraction over 1000.
\(0.222=\frac{222}{1000}\) Now, identify the GCF of the fraction. It is harder with larger numbers, but both numbers are even, so we can, at least, divide by 2.
\(\frac{222}{1000} \div \frac{2}{2}=\frac{111}{500}\) 111 and 500 do not share any common factors, except for 1, so this fraction is in simplest form.
   

 

I will do the next decimal, 0.1515

 

\(0.1515\) Do the same process as above; the decimal extends until the ten thousandths place. Set it to a fraction over that amount, ten thousand.
\(0.1515=\frac{1515}{10000}\) Yet again, it can be hard to determine the GCF, but both numbers end in a 5 or 0, so both are divisible by 5. 
\(\frac{1515}{10000}\div \frac{5}{5}=\frac{303}{2000}\) Yet again, there are no common factors greater than 1, so this fraction is irreducible.
   

 

I will do the next decimal, as well.

 

\(0.0242424\) This extends to the ten millionth place, so put the number over a fraction over ten million.
\(0.0242424=\frac{242424}{10000000}\) The numerator and denominator's final two digits are divisible by 4, so we can divide them by, at least, 4.
\(\frac{242424}{10000000}\div\frac{4}{4}=\frac{60606}{2500000}\) We aren't done yet. The numerator and denominator are both even, so it is divisible by 2.
\(\frac{60606}{2500000}\div\frac{2}{2}=\frac{30303}{125000}\) The numerator and denominator are co-prime, so this fraction is in simplest form.
   

 

Here goes the next one:

 

\(0.5555\) The decimal extends to the ten thousandths place, so make a fraction over ten thousand.
\(0.5555=\frac{5555}{10000}\) Both the numerator and denominator are divisible by 5 because both of them end in a 5 or a 0.
\(\frac{5555}{10000}\div \frac{5}{5}=\frac{1111}{2000}\) 1111 and 2000 have no common factors, so the fraction is simplified completely. 
   

 

And, of course, here is the next one, -0.124124124.

 

\(-0.124124124\) This decimal extends to the billionth place, so set it over a billion. Just put the negative sign in front of the fraction.
\(-0.124124124=-\frac{124124124}{1000000000}\) Both the numerator and denominator's final 2 digits are divisible by 4, so the fraction can be simplified. 
\(-\frac{124124124}{1000000000}\div\frac{4}{4}=\frac{31031031}{250000000}\) There are no more common factors. 
   

 

You are done now!

Jul 30, 2017

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