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Diano4ka-milaya [45]
2 years ago
13

Find the area of a circle if i) radius is 21cm ") diameter is 28cm​

Mathematics
2 answers:
wel2 years ago
8 0

Answer:

  i) 441π cm² ≈ 1385.4 cm²

  ii) 196π cm² ≈ 615.8 cm²

Step-by-step explanation:

The areas of circles with radius 21 cm or diameter 28 cm can be found using the appropriate area formula.

<h3>i)</h3>

The formula for the area of a circle based on its radius is ...

  A = πr²

When the radius is 21 cm, the area is ...

  A = π(21 cm)² = 441π cm² ≈ 1385.4 cm²

<h3>ii)</h3>

The formula for the area of a circle based on its diameter is ...

  A = (π/4)d²

When the diameter is 28 cm, the area is ...

  A = (π/4)(28 cm)² = 196π cm² ≈ 615.8 cm²

yanalaym [24]2 years ago
5 0

Answer:

Before multiplying by pi. 441π cm²

After multiplying by pi. 1384.74 cm²

Step-by-step explanation:

The formula for area of a circle is πr².

r=radius

Square the radius.

21²=441

If they want the answer in this form: 441π cm². If not, then use 3.14 for π.

441*3.14=1384.74

The answer is 1384.74 cm².

Hope this helps!

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The correct question is
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