Home › UP Board Class 10 › mathematics › Areas Related to Circles › The formula for the length of an arc of a circle…
The formula for the length of an arc of a circle of radius r and angle theta (in degrees) is
A(theta/180) × pi × r squared
B(theta/360) × 2 × pi × r
Cpi × r squared
D2 × pi × r
Answer & Solution
Correct answer: B. (theta/360) × 2 × pi × r
1. A full circle (360 degrees) has circumference 2 × pi × r.
2. An arc of angle theta is the fraction theta/360 of that.
3. Hence arc length = (theta/360) × 2 × pi × r.
_Source: NCERT Class 10 Mathematics, Ch 11 "Areas Related to Circles", §11.2_
Related questions
A chord 16 cm long is drawn in a circle of radius 10 cm. The distance of the chord from thA wheel of diameter 84 cm makes 75 revolutions. The distance covered isA square is circumscribed about a circle of radius 7 cm. The area enclosed between the cirTwo concentric circles have areas in the ratio 1 : 4. The ratio of their radii isA circular field of radius 56 m has a path of width 7 m running around it. The area of theThe diameter of a wheel is 70 cm. The number of revolutions to go 11 km isA wire bent into a circle of radius 42 cm is now bent into a regular hexagon. The side of A circle is inscribed in an equilateral triangle of side 12 cm. The area of the region bet