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Math (Quadrilaterals and Polygons)?

0 votes

Hey guys, 
I have been stuck on these two questions for the longest time. I've tried everything. PLEASE HELP!!! 
No.1) 
Find the value of x and y. 

No. 2) 

Find the area of the figure 

asked Jul 16, 2014 in GEOMETRY by anonymous

1 Answer

0 votes

1) From the figure , the trepezoid is isosceles trepezoid .

In an isosceles trepezoid when the sides that are n't parallel are equal in length and both angles coming from parallel sides are equal.

2x + 3y = 12 → (1)

30x + 11 = 112 → (2)

Solving above two equations

To get two equations that contain opposite terms multiply the first equation by 15.

Write the equations in column form and add the equations to eliminate x - variable.

image

The resultant equation is - 34y  = - 68

= (-68)/(-34)

y  = 2

Substitute the value of  y  = 2 in either of the original equations and solve for x.

The first equation:  2x + 3y  = 12

2x + 3(2) = 12

2x  + 6 = 12

2x  = 12 - 6

2 = 6

x  = 6/2

x  = 3

Therfore , the values of x  = 3 and y  = 3.

2) From the figure it is a irregular pentagon.

In this case the irregular pentagon can be split into one rihtangle triangle and trepezoid.

Now we need to find area of each of them and add them together.

  • Area of right angle triangle = 1/2 * base * height

= (13.42 * 12)/2

= 13.42*6

= 80.52 in2

  • Area of the trepezoid = (a + b)h/2

= [(11.75 + 18)6.12]/2

= 91.035 in2

Total area of irregular pentagon = Area of the trepezoid + Area of right angle triangle

= 80.52 in2 + 91.035 in 2

= 171.555 in2

Therfore, area of figure is 171.555 in2.

answered Jul 17, 2014 by david Expert

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