The two displacements are 6.0 m East and 10.0 m at N30ºE.
The angle between East and N30ºE is 60°.

Using the cosine rule:

R\(^2\) = 6\(^2\) +10\(^2\) +2(6)(10)cos60º

R\(^2\) = 36 + 100 +120 (0.5) = 196

R = \(\sqrt{196}\) = 14.0m