The point that divides the segment joining $(1,2)$ and $(3,4)$ in the ratio $1:1$ is

1. A ratio of 1:1 means the mid-point. 2. Mid-point $=\left(\dfrac{1+3}{2},\ \dfrac{2+4}{2}\right)=(2,3)$. 3. So the point is $(2,3)$. _Source: Karnataka SSLC (KSEEB) Class 10 Mathematics, Ch7 'Coordinate Geometry', §7.3_