How can you calculate the length of one side of a triangle given only the other two sides and the total area?

Answer: That will depend entirely on what type of triangle it is but in general:-

Area of any triangle = 0.5*base*perpendicular height

Answer: You'll probably have to use some trigonometry. Use one of the given lengths as the base (horizontal, along the x-axis). Calculate the perpendicular height using this side and the total area. Then use trigonometry to calculate at what angle you need to place the second given side. From this information, you can get the coordinates of the two endpoints (for simplicity, the two given sides should intersect at the origin). Then use the Pythagorean Formula to calculate the length of the third side. - In theory, you could also use Heron's Formula, but solving this formula for one of the sides looks rather complicated. But you could do it with trial and error.