How do you find the arc length of the partial circle?

[tex]\qquad\qquad\huge\underline{{\sf Answer}}♨[/tex]
As we know :
Length of arc = Radius × Angle made by Arc at center [ in radians ]
[tex]\qquad \tt \dashrightarrow \: arc = radius \times angle \: \: ( in \: \: rad)[/tex]
[tex]\qquad \tt \dashrightarrow \: arc = 4 \times \dfrac{3 \pi}{2} [/tex]
[tex]\qquad \tt \dashrightarrow \: arc = 6\pi \dfrac{ }{} \: \: units[/tex]
or
[tex]\qquad \tt \dashrightarrow \: arc = 6\times 3.14 = 18.84 \: \: units\dfrac{ }{} \: \: [/tex]
So
Arc length