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