Question 4: The area of a circle is given by A(r) = πr2, where ‘r’ is the length of the radius (see the graph). Find
(a). A(2.34 in)
(b). A(6.41 m)
(c). A(5/11 in)
Solution
(a).
The given function is A(r) = πr2.
Put r = 2.34, we have,
A(2.34) = π(2.34 × 2.34)
A(2.34) = 3.14159 × 2.34 × 2.34
A(2.34) = 17.212 in2
(b).
The given function is A(r) = πr2.
Put r = 6.41 m, we have,
A(6.41) = 3.14159 × 6.41 × 6.41
A(6.41) = 129.08 m2
(c).
The given function is A(r) = πr2.
Put r = 5/11 in, we have,
A(5/11) = 22/7 × 5/11 × 5/11
A(5/11) = 50/77 = 0.6491 in2
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