Answer:
His friend took one from 61 and added it to 39. That made it easy to mentally add 40 and 60 to get 100. Then he mentally added 28 to 100 to get 128.
Sin(pi/6) would be appropriate as that is 1/2
The proof is because it has a right angle.... I think :)
The answer is B I asked my dad and he is supppperrrr smart lol
1500 pounds since a ton I 2000 just multiply it by 3/4
