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Mathematics 13 Online
OpenStudy (clueless):

In the figure, the ratio of the perimeter of rectangle ABDE to the perimeter of triangle BCD is ___ . The area of polygon ABCDE is ___ square units. part 1 options 2/3 1 3/2 2 Part 2 options 18 22 24 28 Please help me I cant figure this out to save my life and I need to finish by tomorrow or I can't go on my senior trip. I'll fan and give anyone a medal that can help me!

jimthompson5910 (jim_thompson5910):

were you able to find the perimeter of rectangle ABDE?

OpenStudy (clueless):

32?

jimthompson5910 (jim_thompson5910):

what is the base of the rectangle? I.e, what is the distance from D to E?

OpenStudy (clueless):

2

jimthompson5910 (jim_thompson5910):

yep, how about the height? what is the distance from E to A?

OpenStudy (clueless):

6 so the perimeter of the rectangle is 12?

jimthompson5910 (jim_thompson5910):

|dw:1464739528416:dw|

jimthompson5910 (jim_thompson5910):

the rectangle ABDE looks like this

jimthompson5910 (jim_thompson5910):

add up the four sides 2+6+2+6 = 8+8 = 16

jimthompson5910 (jim_thompson5910):

so the perimeter of ABDE is 16 units do you agree with this statement?

OpenStudy (clueless):

yes

jimthompson5910 (jim_thompson5910):

ok now onto the triangle

jimthompson5910 (jim_thompson5910):

how long is segment BD?

OpenStudy (clueless):

6

jimthompson5910 (jim_thompson5910):

yes

jimthompson5910 (jim_thompson5910):

to find the other 2 sides, we will need to use the distance formula have you learned this formula in your lesson?

OpenStudy (clueless):

Not that I found

jimthompson5910 (jim_thompson5910):

have you learned the pythagorean theorem?

OpenStudy (clueless):

a^2 + b^2 = c^2?

jimthompson5910 (jim_thompson5910):

yes

jimthompson5910 (jim_thompson5910):

so we start with this https://cdn.ple.platoweb.com/EdAssets/35d21e00057140ab829a717857a217fa?ts=635375425111030000 what I would do next is draw in red segments as you see in the attached document

jimthompson5910 (jim_thompson5910):

based on this http://assets.openstudy.com/updates/attachments/574e2196e4b056c4b3e61ce0-jim_thompson5910-1464740094550-triangle1.jpg how long is the green segment? how long is the red segment?

OpenStudy (clueless):

4 and 3

jimthompson5910 (jim_thompson5910):

very good

jimthompson5910 (jim_thompson5910):

focus on that triangle and we see this |dw:1464740172111:dw|

jimthompson5910 (jim_thompson5910):

to find the distance from D to C is the same as finding the hypotenuse x

jimthompson5910 (jim_thompson5910):

in this case a = 4 b = 3 c = x c is always the longest side |dw:1464740228995:dw|

jimthompson5910 (jim_thompson5910):

do you know how to use this info to find the value of c?

OpenStudy (clueless):

I honestly have no idea. would that still be 6 or no?

jimthompson5910 (jim_thompson5910):

\[\Large a^2+b^2 = c^2\] \[\Large 4^2+3^2 = x^2\] \[\Large 16+9 = x^2\] \[\Large 25 = x^2\] \[\Large x^2 = 25\] If x^2 = 25, then x = ???

OpenStudy (clueless):

5?

jimthompson5910 (jim_thompson5910):

yes, so the distance from D to C is 5 units this is the same as saying segment DC is 5 units long

jimthompson5910 (jim_thompson5910):

now draw in additional segments to form another right triangle

jimthompson5910 (jim_thompson5910):

what are the lengths of those vertical and horizontal segments?

OpenStudy (clueless):

3 and 4?

jimthompson5910 (jim_thompson5910):

yes, so how long is BC?

OpenStudy (clueless):

5 units?

jimthompson5910 (jim_thompson5910):

yep

jimthompson5910 (jim_thompson5910):

to summarize triangle BCD, so far, we have BD = 6 DC = 5 BC = 5 what is the perimeter of triangle BCD?

OpenStudy (clueless):

16?

jimthompson5910 (jim_thompson5910):

yes

jimthompson5910 (jim_thompson5910):

the perimeter of rectangle ABDE is 16 units the perimeter of triangle BCD is 16 units

OpenStudy (clueless):

so the answer is 1?

jimthompson5910 (jim_thompson5910):

to find `the ratio of the perimeter of rectangle ABDE to the perimeter of triangle BCD` we divide the two values ratio = (perimeter of rectangle)/(perimeter of triangle) = 16/16 = 1

jimthompson5910 (jim_thompson5910):

yes the answer to the first part of the question is 1

OpenStudy (clueless):

so is the second part 24?

jimthompson5910 (jim_thompson5910):

let me check

jimthompson5910 (jim_thompson5910):

You nailed it. Nice job.

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