\nLet the starting point be the origin (0,0) on a 2D plane, with East along the positive x-axis and North along the positive y-axis.
\n1. R walks 1 km to the east: The position is (1, 0).
\n2. He turns to south and walks 5 km: South is in the negative y direction. The position becomes (1, 0 – 5) = (1, -5).
\n3. Again he turns to east and walks 2 km: East is in the positive x direction. The position becomes (1 + 2, -5) = (3, -5).
\n4. After this he turns to north and walks 9 km: North is in the positive y direction. The position becomes (3, -5 + 9) = (3, 4).<\/p>\nThe final position is (3, 4) and the starting position is (0, 0).
\nThe distance from the starting point is the straight-line distance between (0, 0) and (3, 4).
\nUsing the distance formula: Distance = $\\sqrt{(x_2 – x_1)^2 + (y_2 – y_1)^2}$
\nDistance = $\\sqrt{(3 – 0)^2 + (4 – 0)^2} = \\sqrt{3^2 + 4^2} = \\sqrt{9 + 16} = \\sqrt{25} = 5$ km.
\n<\/section>\n