Keith Lee's answer to Varsha's Junior College 2 H2 Maths Singapore question.
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Clue: Find green angle using trigonometry. Then find area of shaded red sector. Few more steps after that.
Date Posted:
5 years ago
Alternative way to find the green angle without using trigo :
Both triangle CBA and DBA are right angled isosceles triangles.
So angle CBA and angle DBA are just 45°
((180°- 90°)/2)
then, angle CBD is the sum of the two angles.
Both triangle CBA and DBA are right angled isosceles triangles.
So angle CBA and angle DBA are just 45°
((180°- 90°)/2)
then, angle CBD is the sum of the two angles.
Oh yes! That’s definitely the most efficient and recommended way
Looking at this question again, I realised that ∠CBD = 90° (angle in a semicircle)
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