How would you know if two vectors are perpendicular?

Annie walked her dog 2 1/4 miles from her house to the dog park and 3/7/8 miles around the park.then she walked the same distance home.how many miles did she walk in all?

Brady has a 20 year fixed rate mortgage for $215,500 with monthly payments of 1,305.89.the annual interest rate is 4%. what is the total cost of the principal and interest for this loan rounded to the nearest dollar

An episode of a television show is 60 minutes long when it originally airs with commercials. on a dvd without commercials, the episode is only 417 minutes long. how many1-minute commercials did the episode include when it originally aired? write and solve an equation to justify your answer.