reserve i, n for Nat,
  x, y, a for Real,
  v for Element of n-tuples_on REAL,
  p, p1, p2, p3, q, q1, q2 for Point of TOP-REAL n;

theorem Th35:
  |.p.| = sqrt |(p,p)|
proof
  |.p.| = sqrt |.p.|^2 by SQUARE_1:22,TOPRNS_1:25
    .= sqrt |(p,p)| by Th34;
  hence thesis;
end;
