Page 32 - ENGINEERING DRAWING

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b. To Construct a regular pentagon given a diagonal, i.e. within a given circle.

Steps of construction:

i. Draw the given circle and insert a diameter AM.

ii. Divide the diameter into the same number of divisions as the polygon has sides.

iii. With centre M draw an arc, radius MA. With centre A draw another arc of the
same radius to intersect the first arc in N.

iv. Draw N2 and produce to intersect the circle in B (for any polygon).

v. AB is the first side of the polygon. Step out the other sides BC, CD, etc.

ABCDE is the required pentagon.