First you would need to solve x. 2x+x+14+x-38=180 4x-24=180 4x=204 x=51 Now plug in the x for all three angle measures. 2(51)=102 degrees 51+14=65 degrees 51-38=13 degrees Final answer is 102 degrees, 65 degrees, 13 degrees
If it's a regular octahedron, then you can calculate it using the formula where is the length of the edge. If it's not regular, you have to calculate the area of each side individually.