Given right triangle ABC with altitude BD drawn to hypotenuse AC. If AB=7 and AD=1, what is the length of AC ? solve this problem without any links I need a real answer

Cassie is traveling 675 miles today to visit her brother and his family. so far, she has stopped for gas three times. at the first stop, she put in 7.1 gallons of gas and paid $23.79. at her second stop, she put in 5.8 gallons of gas and paid $19.08. and, at the third stop, 6.6 gallons and paid $20.39. at which stop did casey pay the most for gas?

Amovie streaming service charges it’s customers $15 a month. martina has $98 saved up. will she have any money left over if she pays for the maximum amount of months she can afford? explain.

Math it's appreciated. (picture provided)