Are you talking about a triangle?
If so, the angles in a triangle add up to 180.
70 + 30 = 100
So c must be 80 because 100 + 80 = 180.
x = 80
1. High-quality materials
2. Earn money
3. Collect antiques
4. Kitchen equipment
5. Traditional patterns
I know he stole the necklace
This is best grammar for your sentence