Q&A - PSLE Math

[Michaelia0816]

A square is incribed in a circle. If the area of the square is 70cm2, what the area of the circles? (Take pi as 22/7)

[Michaelia0816]

Tianzhu,of course that our class is top, this is of course my homework, it even can photo it and post it on twitter.

[Michaelia0816]

Tianzhu, pls help with the question on top of my pervious post, it my last question!

[tianzhu]

Michaelia0816:

A square is incribed in a circle. If the area of the square is 70cm2, what the area of the circles? (Take pi as 22/7)

Hi

Please take a look at this similar question.

Area of the outer square ------ 140

140 ------ d*d where d is the diameter of the circle.

Area of circle -----pi*d^2/4 ----- 22/7*140/4 ------ 110

Hope this helps.

Best wishes

http://farm7.staticflickr.com/6151/6191262010_71cc0ec1fd_z.jpg\">

[Michaelia0816]

Do the 140cm2 get by 70cm2*2

[Michaelia0816]

Now I understand how 140cm2 is get

[Michaelia0816]

Thx :finally finished!:

[charsen]

tianzhu:

charsen:

How to solve this question ?

The sum of 4 numbers is 80.If you add 3 to the first number, subtract 3 from the second number,multiply the third number by 3 d divide the fourth number by 3,the result will be equal.What is the difference between the largest and the smallest of the original numbers.

Hi

First thing first, is such a question within the syllabus?

The original numbers are 12,18,5 and 45.

Difference ------ 45-5 ------ 40

Best wishes

How do you get this numbers?Is It By logical reasoning?I think this is in the syllabus.

[lucky168]

Has anyone used the assessment book "Top school maths, Volume 4A" by Edmund Cheong, Derek Cheong & Vincent Seow? It’s horrible! Has found 4 mistakes so far after doing just 2 papers!

[MathIzzzFun]

charsen:

How to solve this question ?

The sum of 4 numbers is 80.If you add 3 to the first number, subtract 3 from the second number,multiply the third number by 3 d divide the fourth number by 3,the result will be equal.What is the difference between the largest and the smallest of the original numbers.

hi

Hi
after multiplying 3rd number by 3 --> 3u

1st number --> 3u-3
2nd number --> 3u +3
3rd number --> 1u
4th number --> 9u
Total --> 16u = 80
1u --> 5

1st number --> 12
2nd number --> 18
3rd number --> 5
4th number --> 45

cheers.