Physics
posted by Preston .
A particle undergoes three displacements.
The first has a magnitude of 15 m and makes an angle of 30 degrees with the positive x axis. The second has a magnitude of 8.6 m and makes an angle of 149 degrees with the positive x axis. After the third displacement the particle returns to its initial position.
Find the magnitude of the third displacement.
Answer in units of m

convert the two displacements to (x,y) values
add the two x & y values
that will be the final displacement. magnitude is √(x^2+y^2)