Question

find the length of an arcof a circle of diameter 20 cm which substends an angle of 45° at the centre

Answer 1

Diameter of circle=20 cm
Therefore, radius = 10 cm
Length of arc = 45/360 × 2πr
= 1/8 × 2(3.14)(10)
= 1/8 × 20(3.14)
= 1/8 × 62.8
= 62.8/8
= 7.85 cm

Answer 2

radius is equal to 10 cm


$length \: ofarc = 45 \div 360 \times 2 \times 22 \div 7 \times 10$