NumericalEasy1 mark
9(a)
In the figure given, O is the centre of the circle. ∠DAE = 70º, Find giving suitable reasons the measure of:
∠BOD
Topic: Circle theorems
Previous-year question practice database
Answer
Exam answer
From part (i):
∠BCD = 70°
∠BOD is the angle at the centre standing on arc BD.
∠BCD is the angle at the circumference standing on the same arc BD.
Therefore:
∠BOD = 2∠BCD
= 2 × 70°
= 140°
Answer:
∠BOD = 140°.
Explanation
The angle at the centre is twice the angle at the circumference when both stand on the same arc BD.