2. constructions An angle of 90° at a given point on a line

3. constructions Task: Task: C is a point on line AB.  Centre O, radius OC, draw an arc to cut AB again at D.  Join DO and produce it to meet the circle at E.  Mark any point O outside AB.  Join CE.   ECB is 90°.  EC is the perpendicular to AB. Task: Task: C is a point on line AB. Using ruler and compasses construct an angle of 90° at C. Construction: An angle of 90° at a given point on a line C AB D O E Conclusion:

4. constructions Conclusion:   ECB is 90°.  EC is the perpendicular to AB. Task: Task: C is a point on line AB. Using ruler and compasses construct an angle of 90° at C.Task: An angle of 90° at a given point on a line C AB D Task: Task: C is a point on line AB. O E RESTART END SHOW