Sulikhan wrote:

there are couple of questions

16) Find the area of the shaded region in the diagram below.Give your answer in terms of pi

it's a semi cicrcle of diameter 10cm then there is another circle in it.(ANSWER 6.25 PI)

25)Asquare is divided into 3 congruent rectangles.The middle of rectangle is removed and replaced on the side of the original square to form an octagon as shown.

what is the ration of the perimeter of the sqaure to octagon? ( ANSWER 3:5)

27) In the magic square which uses all whole numbers from 7-15 each of the rows columns and diagonals have same total?What is the number of n?7

n

7

14

Q16: Look at picture we can see radius of big circle is 5 and radius of small circle is 2.5. The area of shade is 1/2 big circle- small circle.

Q25: look at picture we can see the long side of rectangle is 3 times the short. Let’s call short one is 1, therefore long one is 3. The perimeter of square is 3x4. The octagon is 20. Ratio is 3/5.

Q27: the total of magic square is 7+8+...15=99 so any line is 99:3=33. Look at picture the top right corner is 33-7-14=12. 15 can not be same line with 14 and 12 because that line will be more than 33, therefore 15 is in middle of left column just under n. Therefore the center number is 33-15-7=11 and n= 33-11-14=8.

Hope that helps.