pakai cara ya jwab nya

      Keliling Lingkaran = 2 x [tex] \pi [/tex] x r
                    138,16 cm = 2 x 3,14 x r
                  2 x 3,14 x r  = 138,16 cm
                        6,28 x r  = 138,16 cm
                                    r  = [tex] \frac{138,16}{6,28} [/tex]
                                    r  = 22 cm

                                MA = r
                                       = 22 cm