The shaded area can be found by subtracting the of the two unshaded circles from the big circle.
6 years ago
Soo Vei Li
If you take a pencil and trace the outline of the shaded part, you will see that the perimeter is the sum of the circumference of the big circle and the 2 smaller circles.
Here's a repost from 9 May: The challenge in this question is finding the area of the two shaded triangles. Each shaded triangle = area big triangle - area SXT = half area of square - 1/2x10x6 = 20. Total area of two shaded triangle is 40. The shaded area in the square TMNO is more straightforward.
6 years ago
Soo Vei Li
And there were some follow-up questions from the solution given...
6 years ago
Mavis Low
Thanks Vei Li! Although I find it hard to assume that the point bet P and Y, to point X to point T, is a straight line. A piece of info like that should be stated in the question? And not left to us to assume?
6 years ago
Soo Vei Li
Yes, you are right. Good point raised 😊
6 years ago
Mavis Low
Asked 9 years ago
SG
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Primary 6
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Geometry
Replies
7
Irene Ong
6 years ago
Mavis Low
Why is angle FEC = 90? EFGH is a rhombus, not a square right?
6 years ago
Irene Ong
This rhombus is actually a sq. My kid got a similar question during his mid yr paper too. From the sch question then I know how to do this question.
6 years ago
Chong Ji Lian
How to assume that this rhombus is a square? There must be a reason to support this right?
6 years ago
Irene Ong
This right angle is show from the original question. It's not drawn by anyone of us.