Draw a line segment ^@AB^@ and bisect it. Also, bisect one of the equal parts.
Answer:
Draw a line segment ^@AB.^@ With center ^@A^@ and radius more than half of ^@AB^@, draw arcs one on each side of ^@AB^@. With center ^@B^@ and same radius, draw arcs cutting previous arcs at ^@P^@ and ^@Q^@ respectively. Join ^@PQ^@ and which intersect ^@AB^@ at ^@C^@. With center ^@A^@ and radius more than half of ^@AC^@, draw arcs on each side of ^@AC^@. With center ^@C^@ and same radius, draw arcs cutting previous arcs at ^@R^@ and ^@S^@ respectively. Join ^@RS^@ and which intersect ^@AC^@ at ^@D^@.