A circle has a center at (3 ,2 )(3,2) and passes through (1 ,1 )(1,1). What is the length of an arc covering (3pi ) /4 3π4 radians on the circle?

1 Answer
Apr 21, 2018

color(blue)((3pisqrt(5))/4)3π54

Explanation:

If the centre of the circle has coordinates (3,2)(3,2) and the point (1,1)(1,1) lies on the circumference, then the length of the radius is the distance between these points. This can be found using the distance formula.

d=sqrt((x_2-x_1)^2+(y_2-y_1)^2)d=(x2x1)2+(y2y1)2

d=sqrt((3-1)^2+(2-1)^2)=sqrt(5)d=(31)2+(21)2=5

If we rotate the terminal side (3pi)/43π4 to form a sector, then the angle subtended by the arc at the centre will also be (3pi)/43π4

Arc length is given by:

rthetarθ

:.

sqrt(5)((3pi)/4)=(3pisqrt(5))/4