Squaring the circle the circular arc b around O with radius , it results S'. Bisect the line segment in D and draw the semicircle b over D. Draw a straight line from O through C up to the semicircle b, it cuts b in E. The line segment is the mean proportional between and , also called geometric mean. Extend the line segment beyond O and transfer twice more, it results F and A, and thus the length of the line segment with the above described approximation value of formula_3, the half circumference of the circle. Bisect the line segment in G
Circle MRT line an LRT line that goes from Paya Lebar to Buona Vista via Serangoon and Bishan to form Circle line Stage 3 and 4 in 2001. Circle line Stage 5 was finalised in February 2002 when Stage 4 was extended from Buona Vista to World Trade Centre to close up the link and to provide connectivity from the west to Sentosa, and it became the full Circle line in the end. Stations in Circle line that were a part of the original Marina line plans include Dhoby Ghaut, Bras Basah, Esplanade, Promenade, Nicoll Highway and Stadium. The part of the previously