Step-by-step explanation:

1) draw a line segment 4 centimetre 2)take a point p outside outside the circle and draw a secant PAB intersecting the circle at a and b 3)produce AP to see such that ap and CP 4)draw a semi circles with CB as diameter 5) draw PD perpendicular to CB , intersecting the semi circle at D 6 ) with p at as centres and PD as radius from dark to intersect the given circle at p and T 7 ) join PT and PM 8 ) then PT and PM are the required tangents