Between 1960 and 1990, the number of farms in the United States decreased by 2.1% per year. In 1960, there were 4 million farms. How many farms were there in 1990?

In this question, write the equation you will use to solve it.

nswer: a   y-axis

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.

sounds & other waves originate from any vibrating object

step-by-step explanation:

infinity is the answer