Solution to the Problem:

Here is the solution:

The diagram represents a quarter of a circle with center A.

Draw segment AB which is a radius of the circle and the hypotenuse of a right triangle with legs 9 and 12.

Using the Pythagorean Theorem, AB = 15.

So, x + 9 = 15, and therefore x = 6.

Similarly, 12 + y = 15, so y = 3.

Therefore x - y = 6 - 3 = 3.




Hari Kishan solved it differently and did not actually solve for x and y, but just x - y, which is what we were looking for:
x+9=y+12 (radius)
⇒ x-y=12-9=3.


Correctly solved by:

1. Dr. Hari Kishan D.N. College,
Meerut, Uttar Pradesh, India
2. Colin (Yowie) Bowey Beechworth, Victoria, Australia
3. Seth Cohen Concord, New Hampshire, USA
4. Davit Banana Istanbul, Turkey
5. Kamal Lohia Hisar, Haryana, India
6. Rosemary Kochi, Kerala, India
5. Mrs. Painter's 2nd block honors precal class Broome High School,
Spartanburg, South Carolina, USA
6. Nova Collins Central High School,
Grand Junction, Colorado, USA
7. Riley Sack Central High School,
Grand Junction, Colorado, USA
8. Kelly Stubblefield Mobile, Alabama, USA