A scientist measures the concentration of dissolved oxygen, in milligrams per litre (y) , in a river. She takes 10 readings at different temperatures, measured in degrees Celsius (x).

Center is (h,k) and point E is (x,y) . We have to find the length of the legs which are used to derive the standard formula of circle .

The length base of the right triangle is (x-h) units.And the length of the right triangle is (y-k) units .

And that's the required lengths of the legs.

Therefore correct options are fourth and last options .