Question

radius of a circle is 21cm then length of arc in the semicircle​

Answer 1

Step-by-step explanation:

Radius = 21 cm

in a semi circle , circumference of semi circle will be......

circumference of semicircle = diameter + arc

2 × pi × r = 2 (21) + arc

$2 \times \frac{22}{7} \times 21 = 42 \times length \: of \: arc$

$length \: of \: arc \: = 44 \times 3 \times \frac{1}{42} \\ = \frac{22}{7} \\ = 3.14 \: {approx}$