Posted by Anonymous on .
A cyclist starts from point X and rides 3 km due west to point Y. At Y he changes direction and rides 5km northwest to point Z.
(a) hw far is he from the starting point, correct to the nearest km?
Find the bearing of the Z frm X to the nearest degree?

physics 
Elena,
The angle XYZ = 135o
According to the Cosine Law
ZX=sqr(XY^2+YZ^22•XY•YZ•cos135)
=sqr(9+25+30 (0.707))= 7.43 km ≈7 km.