NCERT Exemplar Solutions
Class 7 - Mathematics - Unit 9: Perimeter and Area - Multiple Choice Questions
Question 34

Question.  34

34. The circumference of a circle whose area is 81πr², is

(a)

(a) 9πr

(b)

(b) 18πr

(c)

(c) 3πr

(d)

(d) 81πr

Detailed Answer with Explanation:

Area = πR² = 81πr² ⇒ R = 9r.

Circumference = 2πR = 18πr.

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NCERT Exemplar Solutions Class 7 – Mathematics – Unit 9: Perimeter and Area – Multiple Choice Questions | Detailed Answers