An electronic score board of mass 500 kg is suspended from a ceiling making an angle of 70 degrees with the ceiling.The weight is evenly distributed. Determine the tension in the cables in newtons

Draw a free-body diagram of the score board. It's weight of 500Kg * g is a force acting straight down. This force is resisted by the tension in the cable(s), so that the sum of the vertical components of all forces is 0, and also the sum of the horizontal component of all forces is 0. The horizontal force of the tension in a cable that is at 70 degrees to the ceiling is T*cos(70), and the vertical component is T*sin(70). So you will get two simultaneous equations - solve them for T.