Math, asked by garghansika, 10 months ago

21 A wire when bent
when bent in the form of an equilateral triangle encloses an area of 36 v3 cm.
the area enclosed by the same wire when bent to form:
Find
(i) a square, and
(ii) a rectangle whose length is 2 cm more than its width.​

Answers

Answered by preeth3
16
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Answered by Anonymous
3

\bigstar It's always better to know Key Points before Solving the Question! Here are some Key Points which helps us solve this Question easily

  • The Area of an equilateral triangle is given by \sf{\sqrt{3}/4\times Side^2} and The Perimeter of an equilateral triangle is given by \sf{3\times Side} . The Area of a Square is given by the expression \sf{Side\times Side} and The Perimeter of a Square is given by the expression \sf{4\times Side} . The Area of a Rectangle is given by the expression  \sf{Length\times Breadth} and The Perimeter of a Rectangle is given by the expression \sf{2(Lengh+Breadth)}

\rule{315}{2}

First, We will find the Measure of Each Side in the Equilateral Triangle

\longrightarrow\sf{Area\:of\:Equilateral\:Triangle = \sqrt{3}/4\times Side^2}

It is Clearly mentioned Wire bent in the form of an equilateral triangle encloses an area of \sf{36\sqrt{3}\:cm^2} in the Question

\longrightarrow\sf{36\sqrt{3}\:cm^2  = \sqrt{3}/4\times Side^2}

Divide both Sides by the Equation by \sf{\sqrt{3}/4}

\longrightarrow\sf{36\sqrt{3}\:cm^2\div\sqrt{3}/4  = (\sqrt{3}/4\times Side^2)\div\sqrt{3}/4}

\longrightarrow\sf{Side^2 = 36\sqrt{3}\div\sqrt{3}/4\:cm^2 =36\sqrt{3}\times4/\sqrt{3} \times cm^2 }

\longrightarrow\sf{Side^2 = 144\sqrt{3}/\sqrt{3} \times cm^2 = 144\:cm^2 }

Take Square Root on Both Sides of the Equation

\longrightarrow\sf{\sqrt{Side^2} = \sqrt{144\:cm^2}}\longrightarrow\sf{Side = 12\:cm}

Now the Total Length of Wire will be Equal to Perimeter of Wire. Perimeter of Wire = Perimeter of Equilateral Triangle

\boxed{\sf{Total\: Length\: of \:Wire = 3\times Side = 3\times 12\:cm = 36\:cm}}

1) The length of the side of the square is obtained by Dividing Total Length of Wire/Number of Sides in a Square or Total Length of Wire/4

\longrightarrow\textsf{Length of the side of the Square = $\sf{36/4\:cm = 9\:cm}$}

Thus the Area of Square is obtained as follows : \sf{Side\times Side}

\boxed{\longrightarrow\sf{Area\:of\:Square=Side\times Side = 9\:cm\times 9\:cm= 81\:cm^2}}

2) The Perimeter of the rectangle should be 36 cm. Thus the relation obtained is \sf{2(Lengh+Breadth)} . Since the difference between length and breadth is 2 cm, thus the relation obtained is \sf{Length-Bredth=2} . Thus the values of the length and breadth are calculated as follows : \sf{Length-Breadth=2\:cm\longrightarrow Length = Breadth + 2\:cm}

\longrightarrow\sf{Perimeter \:of \:Rectangle = 36\:cm}\longrightarrow\sf{2(Length+Breadth) = 36\:cm}

\longrightarrow\sf{2(Breadth+2\:cm+Breadth) = 36\:cm\quad...\:Since\:Length = Breadth+2\:cm}

\longrightarrow\sf{2(2\times Breadth+2\:cm) = 36\:cm}\longrightarrow\sf{4\times Breadth+4\:cm = 36\:cm}

Subtract 4 cm from Both Sides of the Equation

\longrightarrow\sf{4\times Breadth+4\:cm-4\:cm = 36\:cm-4\:cm }

\longrightarrow\sf{4\times Breadth = 36\:cm-4\:cm = 32\:cm }

Divide Both Sides of the Equation by 4

\longrightarrow\sf{(4\times Breadth)/4 = 32/4\:cm }\longrightarrow\sf{ Breadth = 8\:cm }

Also \sf{Length = Breadth + 2\:cm}\longrightarrow\sf{Length = 8\:cm + 2\:cm=10\:cm}

Thus the Area of Rectangle is obtained as follows : \sf{Length\times Breadth}

\boxed{\longrightarrow\sf{Area\:of\:Rectangle=Length\times Breadth = 10\:cm\times 8\:cm = 80\:cm}}

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