The central angle has a measure of radians calculated by the formula for radian measure is 1.75 radians.
The formula for radian measure to calculate the central angle is given as,
[tex]\theta=\dfrac{s}{r}[/tex]
Here, (r) is the radius of the circle and (θ) is the central angle.
In a circle having a radius of 12 cm and intercepting an arc of 21 cm. Put the value of radius and the length of the arc in the above formula as,
[tex]\theta=\dfrac{21}{12}\\\theta=1.75[/tex]
Thus, the central angle has a measure of radians calculated by the formula for radian measure is 1.75 radians.
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