Geometrical Construction

Draw two circles with radii 15 mm and 20 mm respectively with their centers lying on a horizontal line and 60 mm apart. Draw an arc tangent of radius 55 mm including the circle with radius 20 mm.

A circle of 50 mm diameter rolls on a horizontal surface. Draw the locus of the fixed point on the circumference of the circle for one complete revolution.

Draw a helix for one convolution on a cylinder of 45 mm diameter and 50 mm pitch.