please answer tell fast

Step-by-step explanation:
After travelling 3/4 distance on the circular track, radii of the circle will make right angle and the displacement would be equal to the hypotenuse of this right triangle. Which by Pythagoras theorem is given as:
[tex]displacement \\ = \sqrt{ {400}^{2} + {400}^{2} } \\ = \sqrt{160000 + 160000} \\ = \sqrt{2 \times 160000} \\ = 400 \times 1.414 \\ = 565.6 \: m \\ \\ distance \\ = \frac{3}{4} \times circumference \: of \: circle \\ = \frac{3}{4} \times 2\pi \: r \\ = \frac{3}{4} \times 2 \times 3.14 \times 400 \\ = 6 \times 314 \\ = 1,884 \: m[/tex]