Question

The area of the circle whose diameter is 21 cm is
(a) 346.5 cm²
(b) 37.68 cm²
(c) 18.84 cm²
(d) 19.84 cm²


Answer it with explanation​

Answer 1

Answer:

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==>(a) 346.5 cm²

Explanation

Reason: Here diameter = 21 cm

$∴ Radius r = \: \frac{21}{2} \: cm$

Area of the circle, A = πr²

$∴A = \frac{22}{7} \times \frac{21}{2} \times \frac{21}{2} = 11 \times 3 \times \frac{21}{2} = \frac{693}{2} = 346.5$cm²

Answer 2

Answer:

1)

Solution:

diameter of the circle(d) = 21 cm........( Given)

r = d/2 = 21/2 = 10.5 cm

Now,

A = πr²..........(Given)

= 22/7 × (10.5)²

= 346.5 cm²

Therefore,

The area of the circle having a diameter of 21 cm is 346.5 cm².