iMath | Community

Candy Chan

Asked 9 years ago

Hi need help! The answer is $350 btw how to explain & the working Tks in advance

Replies 1

Pieter Cronje

6 years ago

Adaik Valli

Asked 9 years ago

SG Primary 6 Measurement

We need help for this question. Please help us.

Replies 3

Jason Oon

7r -> 70 r -> 10 2r -> 20 Area of 2 squares = 2 x 20 x 20 = 800 cm2 Area of 4 rectangles = 4 x 20 x 10 = 800 cm2 Area of 3 semi-circles = 3/2 x π x 10 x 10 = 471 cm2 Total area = 800 + 800 + 471 = 2071 cm2

6 years ago

Adaik Valli

Thanks for your help.

6 years ago

Jason Oon

You're welcome

6 years ago

Mavis Low

Asked 9 years ago

SG Primary 5 Measurement

Pls help! Appreciate much!

Replies 6

Jason Oon

6 years ago

Leonie R Tan

Why 300x2?

6 years ago

Jason Oon

If you looked at the dotted lines I've drawn, the shaded triangles are same as the unshaded ones. Hence, total area = 300 x 2

6 years ago

Mavis Low

Yup got it, thanks!

6 years ago

Yeo See Yeong

Is it correct to say that, no matter Joe many triangles there are in ABFE, as long as their height is the same and meet the line EF (where the opposite triangle height is), the shaded area will always be half of the rectangle?

6 years ago

Xavier Sng

You are perfectly correct, Mister Yeo. It is also important that the combined bases of the triangles concerned add up to equal AB, the length of the figure.

6 years ago

Theresa Lim Sin Jin

Asked 9 years ago

SG Primary 6 Number and Algebra

P6 A* Math question. Need hlp.Thanks in advance

Replies 6

Xavier Sng

6 years ago

Xavier Sng

6 years ago

Theresa Lim Sin Jin

Oh wow !! What an effort !! Really appreciate the detial. Thanks million.

6 years ago

Xavier Sng

You are most welcome. I tried to solve it without listing / guess-and-check, but after much exploration I had to throw in the towel. What I tried to do here is to make use of divisibility rules to eliminate unlikely number of printers sold on day one. However the divisibility rules are not taught in primary school. It used to be in secondary one textbooks but the textbooks had been revised and the rules are no longer featured. Please let me know if you wish to learn the divisibility rules here.

6 years ago