A right circular cylinder with base circumference equal to 80 cm, has height equal to 60 cm. It is rotating about its axis at a speed of 30 degrees a second. A boy holds a marker at a point A on the base circumference. He draws a line by taking the marker straight upwards, perpendicular to the base, with a uniform speed of 5 cm per second, and stops at the top at point B. Find the length of the line thus drawn.
give the answer in cm