Which formula would be used to find the measure of angle 1?

One-half(a° + b°).
One-half(a° – c°).
One-half(b° + c°).
One-half(a° – b°).

Asap many people try to eliminate fat from their diets which is one reason it is necessary for humans to eat fat a) fat is the only way to get energy b) every cell in the body must contain fat c)fat stores less energy than polysaccharides d) saturated fats make blood vessels healthier