Mathematics

Find the length XY in the triangle above.

Find the length XY in the triangle above.
  • A.
    √7 m
  • B.
    √6 m
  • C.
    √5 m
  • D.
    √3 m
Correct Answer: Option A
Explanation

XY2 = XY2 + Y2 – 2XY.YZ cos 120
XZ2 = 22 + 12 – 2 x 2 1 cos 120
= 4 + 1 -2 x 2 x 1 x -cos(180 – 120)
= 4 + 1 + 4 cos 60
= 5 + 4 x 1/2
= 5 + 2
= 7
XY = √7 m