Draw an angle of 80° and make a copy of it using ruler and compass.

Steps:

1. Draw a ray OA.

2. Place the centre of the protractor at O and the zero line along OA. Mark a point at 80°.

3. Remove the protractor and join O with the marked point and produce it to B. Then ∠AOB = 80°.

4. To make a copy of ∠AOB, draw any ray PQ.

5. With O as centre and any (suitable) radius, draw an arc to meet ray OA at C and ray OB at D.

6. With P as centre and the same radius (as in step 5), draw an arc to meet PQ at R.

7. Measure the segment CD with the compass.

8. With R as centre and radius equal to CD, draw an arc to meet the previous arc at S.

9. Join PS and produce it to form a ray PT.

Then ∠QPT = ∠AOB = 80°.

Hence, ∠QPT is a copy of ∠AOB.