Which of the following is an example of a census? a) Survey parents whose children attend a local elementary school by randomly selecting 50 parents from the school’s records.
b) The U. S. Population Census
c) Poll students at a college by including a pop-up window in the online registration form. Students have to answer the survey questions before they can register. Try to catch the remaining students at the admissions window when they register in person. d) Weigh every child at an elementary school for a study of physical fitness at the school.

B

Step-by-step explanation:

because its something thats important and needs to be done

the correct option is b

step-by-step explanation:

second option

step-by-step explanation:

the measures of a triangle equal 180. use that to find x.

2x+3x+4x=180

9x=180

9x/9=180/9

x=20

now you know x, you know angle a is 40°, angle b is 60°, angle c is 80°.

because angle a is 40°, the first option doesn't work.

because angle b is 60°, the second option does work.

when you add angle a and b, you get 100°. complementary means it equals 90°, so the third option doesn't work.

when you add angle a and c, you get 120°, which is not 100.