Question

1. Find the circumference of a circle whose radius is-

(i)35cm (ii)4.2cm (iii)15.4cm​

Answer 1

Step-by-step explanation:

(i.) r = 35cm

$2\pi \: r \: = 2 \times \frac{22}{7} \times 35$

2 x 22 x 5

220 cm

(ii.) r = 4.2 cm

$2\pi \: r \: = 2 \times \frac{22}{7} \times 4.2$

2 x 22 x 0.6

26.4 cm

(iii.) r = 15.4 cm

$2\pi \: r \: = 2 \times \frac{22}{7} \times 15.4$

2 x 22 x 2.2

96.8 cm

Answer 2

$\textbf{\huge\underline{\underline\red{Solution} : - }} \\ \\ \textbf{\underline{\underline\red{given} : - } radius\: of \: circle \: is \: } \\ \textbf{35 cm \: \: 4.2 cm \: \: 15.4 cm.} \\ \\ \textbf{\underline{\underline\red{formula} : - }} \\ \\ = > \bold \purple{circumference \: of \:circle \: = 2 \: \pi \: r } \\ \\= > \bold \purple{circumference \: of \:circle \: = 2 \times \frac{22}{7} \times \: 35} \\ \\ = > \bold \purple{circumference \: of \:circle \: = 2 \times 22 \times 5} \\ \\ = > \bold \purple{circumference \: of \:circle \: = 220 \: cm } \\ \\\ \\ = > \bold \purple{circumference \: of \:circle \: = 2 \: \pi \: r } \\ \\= > \bold \purple{circumference \: of \:circle \: = 2 \times \frac{22}{7} \times \: 4.2} \\ \\ = > \bold \purple{circumference \: of \:circle \: = 2 \times 22 \times0.6} \\ \\ = > \bold \purple{circumference \: of \:circle \: = 26.4\: cm } \\ \\\\ \\\ \\ = > \bold \purple{circumference \: of \:circle \: = 2 \: \pi \: r } \\ \\= > \bold \purple{circumference \: of \:circle \: = 2 \times \frac{22}{7} \times \: 15.4} \\ \\ = > \bold \purple{circumference \: of \:circle \: = 2 \times 22 \times2.2} \\ \\ = > \bold \purple{circumference \: of \:circle \: =96.8 \: cm } \\ \\ \bold{ \underline\red{hence \: circumference \: of \: circle \: is \: 220\: cm \: \: 26.4 \: cm \: \: 96.8 \: cm.}} \\ \\ \fcolorbox{red}{white}{i \: hope \: it \: helps \: you.}$