Question

Find which of the following points lie on the circle $x^2+y^2=169$

i) $(3,4)$

ii) $(4,5)$

iii) $(5,12)$

Answer 1

Given the equation of the circle is $x^2+y^2=169$.

As $3^2+4^2=25\ne 169$.

And $4^2+5^2=41\ne 169$ but $5^2+{12}^2=169$.

So the point $(5,12)$ lies on the circle.