Two triangular prisms are similar. The perimeter of one prism is duoble the perimeter of the corresponding face of the other prism

So  if  the sum of the enthalpies of the reactants is greater than the products, the  reaction  will be  exothermic.  if  the products side has a larger enthalpy, the  reaction  is  endothermic. you may wonder why  endothermic reactions, which soak up energy or enthalpy from the environment, even happen

343^x = 49^4-xx = 4-xx+x=42x = 4x = 4/2x = 2therefore x = 2

D. a mountain abd are made by volcanos and tectonic plates