Question

find the area of circle whose radius is is :
(1) 7cm =
(2) 2. 1 m
(3) 3.5km ​

Answer 1

Step-by-step explanation:

ANS 1 Radius -7cm so area will be 153.94cm

ANS 2 Radius -2.1m so area will be 13.85

ANS 3 Radius -3.5km so area will be 38.48

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Answer 2

AnsWer:

• If Radius is 7 cm then, Area = 154 cm²
• If Radius is 2.1 m then, Area = 13.86 m²
• If Radius is 3.5 km then, Area = 38.5 km²

Step-by-step explanation:

1). If radius = 7 cm

Given:

• Radius = 7 cm

To find:

• Area of circle

Now, we know that,

⇒ Area of circle = πr²

⇒ Area of circle = 22/7 × 7 × 7

⇒ Area of circle = 22 × 7

⇒ Area of circle = 154 cm²

2). If radius = 2.1 m

Given:

• Radius = 2.1 m

To find:

• Area of circle

Now, we know that,

⇒ Area of circle = πr²

⇒ Area of circle = 22/7 × 2.1 × 2.1

⇒ Area of circle = 97.02/7

⇒ Area of circle = 13.86 m²

3). If radius = 3.5 km

Given:

• Radius = 3.5 km

To find:

• Area of circle

Now, we know that,

⇒ Area of circle = πr²

⇒ Area of circle = 22/7 × 3.5 × 3.5

⇒ Area of circle = 2269.5/7

⇒ Area of circle = 38.5 km²