Magnitude and Direction

Question

One afternoon, a couple walks three-fourths of the way around a circular lake, the radius of which is 1.99 km. They start at the west side of the lake and head due south to begin with. (a) What is the distance they travel? (b) What is the magnitude of the couple’s displacement? (c) What is the direction (relative to due east) of the couple’s displacement?

It says for part c that the answer must be an exact answer. It doesn't take any letters, which I don't understand.

I've already gotten the right answer for part a. 9.378

I put 3.126 for part c and it said that it was incorrect.

Answer 1

Displacement is the distance between the starting point and end point (point to point). So the displacement in (b) is going to be √ (1.99 ² + 1.99²) using Pythagoras

And for (c), direction of displacement will be 45^° north of east (as you end up NE of starting point)

Mike

Answer 2

Use value of pi as 22/7 = 3.14285714, in place of 3.126 and then check your answer

Answer to (a) should be 9.381

Hope it works