Using the law of cosines, in qrp, if p = 28 km, q = 17 km, r = 15 km, find m

How do i do this activity, is appreciated

What is the simplified form of (3.25x10^3)(7.8x10^6) written in scientific notation?

Hector and alex traded video games. alex gave hector one fourth of his video games in exchange for 6 video games. then he sold 3 video games and gave 2 video games to his brother. alex ended up with 16 video games. how many video games did alex have when he started?