Using ruler and compasses only, draw an equilateral triangle of side 4.5 cm and draw its circumscribed circle. Measure the radius of the circle.
Steps of Construction:
i) Draw a line segment BC = 4.5 cm
ii) With centres B and C, draw two arcs of 4.5 cm radius each which intersect each other at A.
iii) Join AB and AC.
iv) Draw angle bisectors of ∠B and ∠C intersecting each other at O.
v) From O, draw OL ⊥ BC.
vi) Now with centre O and radius OL, draw a circle which will touch the sides of ΔABC