Question

ABCD is a square. With centres B and C and radius equal to the side of the square, circle are drawn to cut one another at E inside the square. ∠ BDE is equal to 

a.22
b.30
c.15
d.37​

Answer 1

Answer:

⇒ In square ABCD, side of square = 5cm.

⇒ Let a=5cm.

⇒ Perimeter of ABCD = 4×a

⇒ Perimeter of ABCD = 4×5

∴ Perimeter of square ABCD = 20cm. ---- ( 1 )

⇒ Area of square ABCD = a

2

⇒ Area of square ABCD = 5

2

∴ Area of square ABCD = 25cm

2

. ----- ( 2 )

⇒ In square PQRS,

⇒ Perimeter of square PQRS = 40cm [Given] --- ( 3 )

⇒ Perimeter of square PQRS = 4×b

⇒ 40=4×a [From ( 3 )]

∴ b=10cm

⇒ Area of square PQRS = b

2

∴ Area of square PQRS = 100cm

2

------ ( 4 )

From ( 1 ) and ( 3 ) we get,

⇒

per(PQRS)

per(ABCD)

=

40

20

=

2

1

From ( 2 ) and ( 4 ) we get,

⇒

Ar(PQRS)

Ar(ABCD)

=

100

25

=

4

1