Question

18. If the side of a square is increased by 30%, its
area is increased by
(a) 29 %
(b) 30 %
(c) 69 %
(d) None​

Answer 1

A = a^2

when a is increased by 30 %

a' = a + 0.3a = 1.3a

new area = (a')^2

new area = (1.3)^2 a^2

new area = 1.69 *a^2

new area % = 169%

new area increasement = 69%

69% hope it helped you.......

Answer 2

Answer:

Correct option is ( c ).

Step-by-step explanation:

Let the length of side of square be a units.

From the properties of square :

• Area of square = ( length of side )^2

Thus,

= > Original area of the square = ( length of it's side )^2

= > Original area of the square = ( a unit )^2

= > Original area of the square a^2 unit^2

If side of square is increased by 30% :

= > New length of side of square = a unit + 30% of a unit

= > New length of side of square = a{ 1 + ( 30 / 100 ) unit

= > New length of side of square = a x ( 130 / 100 ) = 13a / 10 unit

Now,

= > New area of square = ( 13a / 10 unit )^2

= > New area of square = 169a / 100 unit^2

Thus,

= > Area is increased by = { 169a^2 / 100 }{ a^2 } x 100 %

= > Area is increased by = 169%

Hence,

Increase in area = 169% - 100% = 69%

Hence the required option is ( c ).