Question

The perimeter of a rectangle is 98cm and its breadth is 9cm. find its :-
(1)length
(2)length of diagonal
(3)area

Answer 1

Let the length be a

Perimeter = 2 ( Length + width)

=> 98 = 2 (a + 9)

=> 49 = ( a + 9)

=> a = 40


Length = 40 cm

Diagonal = sqrt ( Length^2 + width^2)

= sqrt ( 40^2 + 9^2)

= sqrt ( 1600 + 81)

= sqrt ( 1681)

= 41 cm

Now,

Area = Length × Width

= 40 × 9

= 360 cm^2

Answer 2

We know,

Perimeter = 2( length + breadth )

=> 98 = 2( 9 + length )

=> 49 = 9 + length

=> 49 - 9 = length

=> 40 cm = length






By Pythagoras theorem,

( breadth )² + ( length )² = ( diagonal )²

=> 9² + 40² = diagonal²

=> 81 + 1600 = diagonal²

=> 1681 = Diagonal²

=> 41 cm= diagonal of rectangle






Area = length × Breadth


Area = 40 × 9

Area = 360 cm²

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