Draw a circle and two lines parallel to a given line such that one is a tangent and other a secant to the circle

Draw a line l ,also draw a line m parallel to l at a distance of 4 cm.

Draw a line parallel to a line l at a distance of 3.5 cm from it .

Draw a circle of radius 6cm. From a point 10 cm away from its centre, construct the pair of tangents to the circle and measure their lengths.

Two different non-parallel lines meet the circle abs(z)=r . One of them at points a and b and the other which is tangent to the circle at c. Show that the point of intersection of two lines is (2c^(-1)-a^(-1)-b^(-1))/(c^(-2)-a^(-1)b^(-1)) .

Two lines parallel to the same line are ........... to each other.

In fig., two circles with centres O, O' touch externally at a point A. A line through A is drawn to intersect these circles in B and C. Prove that the tangents at B and C are parallel.