Three vectors A, B and C are such that vector A = vector B + vector C and their magnitude

Question

Three vectors \(\vec A,\vec B\ and\ \vec C\) are such that \( \vec{A} = \vec{B} + \vec{C}\) and their magnitude are 5, 4 and 2 respectively. What will be angle between \(\vec{A} \ and \ \vec{C}\)?

Answer 1

\(\therefore\ \theta = \cos^{-1}\left(\frac{13}{20}\right) = 49.5^\circ\)