In the figure below, QRST and RSLK are squares. P and M are centres of square KLSR and QRST respectively. N is the centre of RS. If QK = 84 m, 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 42
= 132 m
Circuference of four small semicircles
= 4 x
12 x
227 x 21
= 132 m
Circumference of two quadrants
=
14 x 2 x
227 x 42
= 66 m
Perimeter of the shaded region
= 132 + 132 + 66
= 330 m
(b)
Area of big circle
=
227 x 21 x 21
= 1386 m
2Area of two shaded quadrant
=
12 x
227 x 21 x 21
= 693 m
2 Area of shaded region
= 1386 + 693
= 2079 m
2 Answer(s): (a) 330 m; (b) 2079 m
2