1.1.3 Vector Algebra

Problem: 1. Find the angle \( C \) in the triangle \( A B C \), where \( A=(2 ; \Gamma ; H), B=(3 ; H ; \Gamma), C=(-3 ; 1 ; \Gamma) \). 2. Find the area of the triangle \( A B C \). 3. Find the volume of the tetrahedron \( A B C D \), where \( \quad A=(1 ; \Gamma ; H), \quad B=(-3 ; H ; \Gamma) \), \( C=(\Gamma ; 3 ;-1), D=(2 ; 7 ; \Gamma) \). Where \( \Gamma=2, H=2 \).