Question

The length of a rectangular field is increased by 30% and breadth is decreased by 30%.what is the percent increase or decrease in it's area?​

Answer 1

GivEn:

• The length of a rectangular field is increased by 30%.
• And, breadth is decreased by 30%.

To find:

• The percent increase or decrease in it's area.

Solution:

Let the length be x & let breadth be y.

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« Now, Finding new length and new breadth,

New length,

⇒ x + 30/100x

⇒ 130/100x

⇒ 13/10x

New breadth,

⇒y - 30/100y

⇒100 - 30/100y

⇒8/10y

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« Now, Let's find new area,

⇒13/10 × 8/10 xy

⇒104/100 xy

⇒xy + 4/100 xy

∴ Hence, Area is increased by 4%.

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★ More to know :

• Area of rectangle = length × breadth
• Diagonal of rectangle = √(length² + breadth²)
• Area of square = side × side
• Perimeter of square = 4 × side
• Diagonal of square = √2 × side

Answer 2

Answer:

Letthelenghtsandbreadthsinitiallybexandy

Area=xy

Newlength=1.3x

Newbreadth=1.3y

Newarea=1.69xy

Increase=69%