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Before we start, let’s Note on the use of PI (π) We understand that PI can be expressed as 3.14 or
We shall use PI
Radius = r = 7 Area = π × r = π × 7 = π × 7 × 7 but π = = =
Remember that Diameter is twice a radius. So in order to get a radius from diameter, divide it by 2. Radius = Diameter ÷ 2 Radius = 28 ÷ 2 Radius = r = 14 cm Area = π × r = π × 14 = π × 14 × 14 but π = = =
Area = = ½ x 3.14 x 10 x 10 = ½ x 314 =
Area = ¾ x π × r
= 1848 m
Circumference =
¾ x Therefore Circumference =
Area = θ = 18°, π = 3.14, r = 4cm Area = = =
Circumference = θ = 18°, π = 3.14, D = r x 2 = 8cm Circumference = = = 1.256 + 8 =
Area = θ = 140°, π = Area = =
Circumference = θ = 140°, π = Circumference = = 51 = 93 *************** END ***************
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