parallelogram angle

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parallelogram angle

by jeevan.Gk » Sat Jan 03, 2009 12:01 am
Each side of a certain parallelogram has length 6 . If the area is 18.
Which of the following is the measure of one of its angles.

a. 30
b. 45
c. 60
d. 90
e. 120
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Re: parallelogram angle

by logitech » Sat Jan 03, 2009 12:11 am
So the area is 18

6 x HEIGHT = 18

HEIGHT = 3 from the graph you can see that it is a 3-6-3sqrt(3) triangle with 30,60, 90 degrees

So I would choose A) 30
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by Rashmi1804 » Fri Mar 20, 2009 1:22 pm
Logitech,

The area given here is the area of the parallellogram {rhombus} right ??
So how can it be 6*ht = 18 ??

Area of the rhombus = 1/2 * product of the diagnols of the rhombus....

Could you please explain your solution in details ??

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by DanaJ » Fri Mar 20, 2009 1:27 pm
Rashmi1804: A rombus is a parallelogram equal sides. A parallelogram only has pairs of equal sides. This is why the formula for the area provided by logitech is correct.

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by Rashmi1804 » Fri Mar 20, 2009 1:36 pm
DanaJ ..I still dint understand how the area is equal to ht *one of the sides...

if it is area= l*b then it is be 6*6 = 36 ...isnt it ?

I checked out for formulae to calc area of the rhombus....all i got is area is half of product of it's diagnols :cry:

Okiee....temme onething....area of a square with s=6 and area of a rhombus with s=6 are not equal...are they ??

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by Stuart@KaplanGMAT » Fri Mar 20, 2009 2:35 pm
Rashmi1804 wrote:DanaJ ..I still dint understand how the area is equal to ht *one of the sides...

if it is area= l*b then it is be 6*6 = 36 ...isnt it ?

I checked out for formulae to calc area of the rhombus....all i got is area is half of product of it's diagnols :cry:

Okiee....temme onething....area of a square with s=6 and area of a rhombus with s=6 are not equal...are they ??
A rhombus is a parallelogram, just like a square and a rectangle are both parallelograms. The area of any parolellogram is base * height, which is only the same as length times base for squares and rectangles (because of the 90 degree angles).
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by moorthy76 » Mon Mar 23, 2009 9:28 am
can we use the formula Area = side x side x sin of angle?

WE will get 6 x 6 x sin angle = 18

Sin angle = 1/2

Angle is 30.

Is this correct?
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