JEE PYQ: Circle Question 15
Question 15 - 2020 (03 Sep Shift 1)
The diameter of the circle, whose centre lies on the line $x + y = 2$ in the first quadrant and which touches both the lines $x = 3$ and $y = 2$, is ______.
Show Answer
Answer: 3
Solution
Center $(k, 2-k)$, first quadrant. Touches $x = 3$: $|3-k| = r$. Touches $y = 2$: $|2-(2-k)| = k = r$. So $3 - k = k \Rightarrow k = 3/2$, $r = 3/2$. Diameter $= 3$.