The diameter of a spherical bob is measured using a vernier callipers. \( 9 \) divisions of the main scale, in the vernier callipers, are equal to \( 10 \) divisions of vernier scale. One main scale division is \( 1 \, \text{mm} \). The main scale reading is \( 10 \, \text{mm} \) and \( 8^{\text{th}} \) division of vernier scale was found to coincide exactly with one of the main scale division. If the given vernier calliper has positive zero error of \( 0.04 \, \text{cm} \), then the radius of the bob is ______ \( \times 10^{-2} \, \text{cm} \) .