We use cookies to personalise content and advertisements and to analyse access to our website. Furthermore, our partners for online advertising receive pseudonymised information about your use of our website. cookie policy and privacy policy.
 
+0  
 
0
157
4
avatar+2448 

I did try to do this but seriously don't know if what i'm doing is right. Do I have to do pythagorean theorem? 

 Dec 3, 2018
 #1
avatar+100519 
+2

The perimeter is all solved using the distance formula, RP

 

The formula for the distance between two points is given by

 

√ [ (subtract the x coordinates of the two points)^2 + (subtract the y coordinates)^2 ]

 

So....for instance....the distance between A and B is

 

√ [ ( -2 - 2)^2 + ( -1 -1)^2 ] = √ [ (-4)^2 + (-2)^2] = √ [16 + 4] = √20 = 2√5

 

Now..using this example..compute the distances between

A and D

D and C

C and B

 

Add these four distances....this will be the perimeter

 

Do this part first....then....I will show you how to calculate the area

 

Let me know if you run into trouble......

 

 

cool cool cool

 Dec 3, 2018
 #2
avatar+2448 
+1

I got:

2sqrt(5) for A and D

sqrt(3i) for D and C

C and B is sqrt(9) sqrt(5)

RainbowPanda  Dec 3, 2018
 #3
avatar+100519 
+2

AD is correct !!!

 

And you got BC correct.... we can simplify it as   3√5

 

Let's look at DC.....

√ [ ( -4 - (-1) )^2 + ( -5 - (-5) )^2 ] =  √ [ ( -3)^2 + ( 0 )^2] = √9 = 3

 

So.... the perimeter is

 

AB + AD + DC + BC =

 

2√5 + 2√5 + 3 + 3√5 =

 

7√5 + 3   units ≈  18.65 units

 

You did pretty well....!!!!

 

The area is a little tricky, RP.....I'll get back to it in just a bit.....I have a few more questions to get to....just hold on...!!!

 

 

cool cool cool

 Dec 3, 2018
 #4
avatar+100519 
+2

Area....

 

We have a quadrilateral with two parallel sides AD and BC...so....this is a trapezoid

 

The area is

 

(1/2) height of trapezoid * ( sum of the base lengths)

 

The bases are DC and AB.....we know these

 

The height is the tricky part....it is found as:

[ The y coordinate of B - The y coordinate of C ] =  [  1 - (-5) ] = [ 1 + 5] = 6 units

 

So.....the area is

 

(1/2) (6) ( 3 + 2√5 )   ≈    22.42 units^2

 

And that's it....!!!

 

 

cool cool cool

 Dec 3, 2018

22 Online Users

avatar
avatar
avatar
avatar