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PSLE Mathematics

Question post on Sun, 18/09/2016 1:14pm

Can anyone help me with these question. Thank you.

Answer

Ender · Answer 1 · Post on Sun, 18/09/2016 3:06pm

If you cut the square into half, it is made of 2 triangles with base =2R and height =R

R is the radius.

Area of one of the triangle = 98/2 = 49 cm²

1/2 (2R) .R = 49 cm²

R² = 49

R =7 cm

Area of circle = 22/7 X 7 X7 = 154 cm²

Shaded parts = 154 -98 = 60 56cm²

Edit note: careless mistake with the calculator. Correction made. Answer is 56 cm² and not 60.

Ender · Answer 2 · Post on Sun, 18/09/2016 3:06pm

If you cut the square into half, it is made of 2 triangles with base =2R and height =R

R is the radius.

Area of one of the triangle = 98/2 = 49 cm²

1/2 (2R) .R = 49 cm²

R² = 49

R =7 cm

Area of circle = 22/7 X 7 X7 = 154 cm²

Shaded parts = 154 -98 = 60 56cm²

Edit note: careless mistake with the calculator. Correction made. Answer is 56 cm² and not 60.

ChiefKiasu · Answer 3 · Post on Sun, 18/09/2016 9:33pm

I really like your lateral thinking skills. I would have tried to square root the square and get into all kinds of trouble!

Ender · Answer 4 · Post on Sun, 18/09/2016 10:34pm

Thanks, but this is actually how the P5 and P6 are taught. I learned this just two years ago when I began coaching my son for P5 til PSLE.. I have to in a way ‘relearn’ primary school math to be in line with MOE syllabus. His math teacher helps too, she pointed his mistakes out and I make sure his follows thru with her correction. In fact I started out posting some P5 questions here then, and learn from the experts here.

Else, I would like you solve it with brute force. Square root to get the sides of the square too..

ChiefKiasu · Answer 5 · Post on Sun, 18/09/2016 10:53pm

I’m just glad to get to learn from you and other contributors. Actually P6 maths is pretty good at stopping me from getting senile. Keeps our minds sharp! 🙂