The angles of the triangle are 8: 4: 3 Determine the magnitude of each angle.

The theorem on the sum of the angles of a triangle says: The sum of all the interior angles of any triangle is 180 degrees: angle 1 + angle 2 + angle 3 = 180 degrees. Let x be the coefficient of proportionality, then angle 1 = 8x, angle 2 = 4x, angle 3 = 3x: 8x + 4x + 3x = 180; 15x = 180; x = 180/15 (the main property of the “cross to cross” proportion); x = 12. Then angle 1 = 8x = 8 * 12 = 96 (degrees), angle 2 = 4x = 4 * 12 = 48 (degrees), angle 3 = 3x = 3 * 12 = 36 (degrees).
Answer: angle 3 = 36 degrees, angle 2 = 48 degrees, angle 1 = 96 degrees.