What is the standard error of the proportion if 80% of the 1,200 respondents in a yes/no survey answered "no"?

In triangle △abc, ∠abc=90°, bh is an altitude. find the missing lengths. ab=9, and ac=12, find hc.

Select true or false to tell whether the following conditional p q is true or false. use the truth table if needed. if a week has seven days, then a year has twenty months.

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?