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.
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
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
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!
