From the given description above, we can conclude that the lamp suspended to the wall forms an oblique triangle. The first side measures 43 centimeters with an angle 50° to the horizontal and the other side measures 35 centimeters with 70° to the horizontal. We can use cosine law here to get the length of the other side.
c² = a² + b² - 2abcosC
c² = 43² + 35² - 2(43)(35)cos(180°-70°-50°)
c = 39.61 centimeters
