The diameters of a steel ball and a hole in an aluminium plate at 20 °C are 0.90000 cm. and 0.8990 cm respectively. At what temperature (the same for both) will the ball just pass through the hole? (Take: a steel 1.10 × 10^-5 °C^-1; a Al=2.20 x 10^-5°C^-1)