WAEC - Further Mathematics (2009 - No. 12)
An arc of length 10.8 cm subtends an angle of 1.2 radians at the centre of a circle. Calculate the radius of the circle.
12.6 cm
12.0 cm
9.6 cm
9.0 cm
คำอธิบาย
Length of arc (in radians) = \(r \theta\)
\(10.8 = 1.2r\)
\(r = \frac{10.8}{1.2} = 9.0 cm\)