Draw an angle of measure 45° and bisect it.

Step 1: Draw a line AB. Place the centre of the protractor on point A. Coincide AB with the protractor line. Mark C=45. Join AC.

Step 2: Draw an arc cutting AB at D and AC at E.

Taking D as centre and lenth more than the arc DE cut an arc. Repeat for E.

Step 3: let they intersect at point X. Draw a line joining AX aand extend it to F. Measure angle FAB.