Answer:
26
Step-by-step explanation:
The sum of angles in a triangle is 180 degrees, use this and set up an equation;
x + ( 4x -5 ) + 55 = 180
Simplify
x + ( 4x - 5 ) + 55 = 180
5x + 50 = 180
Inverse operations;
5x + 50 = 180
-50 - 50
5x = 130
/5 /5
x = 26
For part A add up all your students then add up all your students that like bike riding and skating (80+90) divide that by the total number of students who took the survey
For Part be put 20+40 over the toatl number of student then simplify