"What's the radius?" asked Harry.
"That's for you to find out."
Harry thought a moment, divided three and a half by two, and setting his compasses at 13⁄4 , drew the circle.
"Now divide the circumference into three equal parts."
Fig. 21. Triangle, hexagon and star
The boy puzzled over this for a moment, then marked off the radius, cutting the circumference into six parts, as if for a hexagon, and erased every other point, leaving three.
"Draw radial lines from these points to the centre."
"Easy," remarked Harry, and drew a line from each point to the centre with the edge of one of his triangles.