PSLE The figure is formed by two identical circles at K and M. KMLN is a square and the length of LM is 14 cm. (Take π = 3.14)
- Find the perimeter of the unshaded part.
- Find the total area of the shaded parts.
(a)
Diameter of the circle
= 2 x 14
= 28 cm
Perimeter of the unshaded part
=
12 x 3.14 x 28
= 43.96 cm
(b)
Area of the unshaded part
= Area of the semicircle - Area of the triangle
=
12 x 3.14 x 14 x 14 -
12 x 28 x 14
= 307.72 - 196
= 111.72 cm
2 Area of the circle
= 3.14 x 14 x 14
= 615.44 cm
2 Total area of the shaded parts
= 2 x (Area of the circle - Area of unshaded part)
= 2 x (615.44 - 111.72)
= 2 x 503.72
= 1007.44 cm
2 Answer(s): (a) 43.96 cm; (b) 1007.44 cm
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