When do we say that a matrix is orthogonal? Share with your friends Share 1 Hemali Hansora answered this A matrix is an orthogonal matrix if where A^T is transpose of A. 0 View Full Answer Reshma Immaculate answered this A square matrix A is said to be orthogonal if (A^T)A =I,'T' stands for transpose and 'I' stands for identity. 0 Naman Dixit answered this any square matrix A is said to be a orthogonal matrix if..AA' = A'A = I(identity matrix)or we can say A^T = A^-1 0