Two angles are said to be linear if they are adjacent angles formed by two intersecting lines. The measure of a straight angle is 180 degrees, so a linear pair of angles must add up to 180 degrees.
Answer:
b) 29π mm²
Step-by-step explanation:

C = number of parents
c+9 = number of children
2c+9=25
2c=16
c=8
8 parents, 17 children
Answer:
f(6) = 3(6) - 9
Step-by-step explanation:
y = 3(6) - 9
y = 18 - 9
y / f(x) = 9