I’m am very confused with this

An alternative to car buying is to make monthly payments for a period of time, and then return the vehicle to the dealer, or purchase it. this is called

Find the measurement of angle b in the following triangle

Amanufacturer knows that their items have a normally distributed lifespan, with a mean if 9.1 years, and standard deviation of 2.9 years. if you randomly purchase one item, what is the probability it will last longer than 10 years?