How did they get 3/4 ?

someone please help me explain

1. are the triangles similar and if so why? what is the value of x? show your work.

Fred has a spinner that is split into four equal sections: red, blue, green, and yellow. fred spun the spinner 688 times. which of the following would be a good estimate of the number of times the spinner lands on the green section? a. 269 b. 603 c. 344 d. 189

Aquadratic equation in standard from is written ax^2= bx+c, where a,b and c are real numbers and a is not zero?