PSLE The figure is formed by two identical circles at T and V. TVUW is a square and the length of UV is 3.5 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 3.5
= 7 cm
Perimeter of the unshaded part
=
12 x 3.14 x 7
= 10.99 cm
(b)
Area of the unshaded part
= Area of the semicircle - Area of the triangle
=
12 x 3.14 x 3.5 x 3.5 -
12 x 7 x 3.5
= 19.2325 - 12.25
= 6.9825 cm
2 Area of the circle
= 3.14 x 3.5 x 3.5
= 38.465 cm
2 Total area of the shaded parts
= 2 x (Area of the circle - Area of unshaded part)
= 2 x (38.465 - 6.9825)
= 2 x 31.4825
= 62.965 cm
2 Answer(s): (a) 10.99 cm; (b) 62.965 cm
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