Since a triangle is 180 degrees ans the triangle is on the right is equal to the triangle on the left, all you have to do is take 180 and subtract 86 and 53 from it to get 41. There's also the fact that the length of all the sides are the same so that can also mean that the angles are the same.
Complete the sentences regarding demand. The demand for inferior goods increases with a decrease in income, whereas public are goods that cannot be bought or sold.