i. Draw three parallel lines.
ii. Label them as l, m, n.
iii. Draw transversals t1 and t2 .
iv. AB and BC are intercepts on transversal t1 .
v. PQ and QR are intercepts on transversal t2 .
vi. Find ratios AB/BC and PQ/QR. You will find that they are almost equal. Verify that they are equal.