Rahul moved 10 meters towards the south from point A to B. Then he took a left…

When a path consists of two segments that meet at a right angle, the straight-line distance between the start and end points is the hypotenuse of a right triangle: AC2 = AB2 + BC2 (the Pythagorean theorem), where AB and BC are the two perpendicular legs and AC is the hypotenuse.

1. Rahul walks 10 meters south from A to B, so AB = 10 meters.

2. Facing south, a left turn points him east, so he walks 15 meters east from B to C, giving BC = 15 meters.

3. The south leg AB and the east leg BC are perpendicular, so triangle ABC is right-angled at B.

4. By the Pythagorean theorem, AC2 = AB2 + BC2 = 102 + 152 = 100 + 225 = 325.

5. AC = √325 ≈ 18.03 meters, which rounds to 18 meters.

Squaring the nearest whole numbers confirms this: 182 = 324 and 192 = 361, and 325 sits just above 324 — consistent with a hypotenuse of approximately 18 meters.