Question

A, b, c and d are points on the circumference of a circle, centre o.

ed is a tangent to the circle.
angle odb = 25 degrees.
work out angle bad.
you must give a reason for each stage of your working.

Answer 1

• Arc DB measures 25 degrees (the measure of a central angle is equal to the measure of the arc it intercepts)
• Angle BAD measures 12.5 degrees (an angle inscribed in an arc has half the measure of the arc it is inscribed in)