Trisecting a Right Angle

Let BAC be the give right angle.

• With centre A and any convenient radius , draw an arc cutting AB at Q and AC at P
• With the same radius and centres P and Q , draw arcs cutting the arc of step a) at R and S respectively. 
• Draw lines joining A with P and Q. AP and AQ trisect the right angle BAC.

                 Thus ∠BAR = ∠RAS = ∠SAC = 1/3 ∠BAC
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