HELP HAVING A BAD DAY FREE 30 POINTS IF CORRECT AND 5 STARs AND A THANKS Find the ratio a:b if it is given that:3a=8b

Astick 2 m long is placed vertically at point b. the top of the stick is in line with the top of a tree as seen from point a, which is 3 m from the stick and 30 m from the tree. how tall is the tree?

Which of the following is not a subset of {1,2,3}?

What is the length of the segment, endpoints of which are intersections of parabolas y=x^2− 11/4 x− 7/4 and y=− 7 /8 x^2+x+ 31/8 ?