Question

Construct a regular pentagon in a circle of radius $3.6$ cm.

Answer 1

• Draw a circle of radius $r=3.6cm$
• Calculate the length $l$ of each side of the regular polygon of $n$ sides: $l=2\times r\times \sin \left(180/n\right)$
• Set the compass to length $l$
• Start at any point $A$ on circle and mark an arc of length $l$
• Mark another arc and continue this process until the arc touches the first point.
• Join the arcs using ruler.