In the figure below, RSTU and STML are squares. Q and N are centres of square LMTS and RSTU respectively. P is the centre of ST. If RL = 70 cm, take π as
227 and find
- the perimeter of the shaded region,
- the area of the shaded region.
(a)
Circumference of big circle
=
227 x 35
= 110 cm
Circuference of four small semicircles
= 4 x
12 x
227 x 17.5
= 110 cm
Circumference of two quadrants
=
14 x 2 x
227 x 35
= 55 cm
Perimeter of the shaded region
= 110 + 110 + 55
= 275 cm
(b)
Area of big circle
=
227 x 17.5 x 17.5
= 962.5 cm
2Area of two shaded quadrant
=
12 x
227 x 17.5 x 17.5
= 481.25 cm
2 Area of shaded region
= 962.5 + 481.25
= 1443.75 cm
2 Answer(s): (a) 275 cm; (b) 1443.75 cm
2