The area of parallelogram WXYZ is approximately 45 square units. Trigonometric area formula: Area = 1/2absin(C). What is the approximate perimeter of the parallelogram? 5 units 15 units 30 units 40 units

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Answer:

C. 30 units. Just took the test and got it right


Answer:

As, it is given that , Area of Parallelogram W X Y Z= 45  square units.

Area of Δ [tex]=\frac{1}{2}absinC[/tex]

As, diagonal of parallelogram divides it into two congruent triangles and congruent triangles have equal area.

So, Area (Δ W Y Z)= Area (Δ W X Y)

Area (Δ W X Z) =Area (Δ X Y Z)

Area (Δ WYZ)  [tex]=\frac{1}{2}(WZ)*(ZY)sinZ[/tex]

[tex]WZ*ZY Sin Z=22.5 *2\\\\ WZ* ZY*SinZ=45\\\\ Similarly, WX*XY*SinX=45\\\\ Similarly, WX*WZ*SinW=45\\\\ Similarly, XY*ZY*Sin Y=45[/tex]

As, Opposite sides as well as Opposite angles of Parallelogram are equal.

Adding all the equation written above,

2(WZ*ZY*Sin Z )+ 2(WX*WZ*SinW)=180

2 * WZ *ZY(Sin Z +Sin W)=180

WZ *ZY(Sin Z +Sin W)=90

Consider the case when , SinZ=SinW=1, when the parallelogram turns into rectangle.

Area of Parallelogram which is rectangle =45 square units

L*B=45

Perimeter of Parallelogram = 2 * (L +B)

[tex]P=2 L +2* \frac{45}{L}\\\\ P =2 L + \frac{90}{L}[/tex]

Differentiating Once w.r.t L

[tex]P'=2-\frac{90}{L^2}[/tex]

For maxima or minima

L²=45

L= 6.70 units

Gives, B= 6.72 units

Perimeter = 2 × (L +B)

             = 2 × (6.70 +6.72)

             =2 × 13.42

              = 26.84

As, area of parallelogram is smaller than area of rectangle having same dimension.

So, Approximate perimeter of Parallelogram = 30  units.

Option C: 30 units

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