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Solution

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Solution

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Solution

Given circle: $ x^2+y^2-2x-4y-20=0 $ $ \Rightarrow (x-1)^2+(y-2)^2=25 $ Centre $=(1,2)$, radius $=5$ New circle also radius $=5$ Since they touch externally, centres lie on line joining and midpoint is $(5,5)$ $ \Rightarrow \frac{h+1}{2}=5,\ \frac{k+2}{2}=5 $ $ \Rightarrow h=9,\ k=8 $ Equation: $ (x-9)^2+(y-8)^2=25 $

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Solution

Complete square: $(x+2)^2 + (y+3)^2 = 0$ Represents a single point ⇒ point circle

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Solution

Area of plot $= \frac{79200}{700} = 113.14\ \text{sq.m (approx)}$ Using $ \pi r^2 = \text{Area}$ $\frac{22}{7} \times r^2 = 113.14$ $r^2 = 36$ $r = 6\ \text{m}$