A certain coin is a circle with diameter 18mm. What is the exact area of either face of the coin?

81pi mm^2

Step-by-step explanation:

The radius is 1/2 the diameter, and is used in finding the area of a circle.

The formula for this is

A = pi(r)^2

So the formula you would use is

A = pi (9)^2

= 81pi

Usually teachers accept it in terms of pi, but if not, you can use 3.14 and multiple it.

I hope this helped!

191 students play sports and ninety-seven 10th graders were surveyed.

step-by-step explanation:

x = -4

step-by-step explanation:

- 20 - 4(x + 3) = 4x

=> -20 - 4x - 12 = 4x

=> - 32 -4x = 4x

=> -32 = 4x + 4x

=> - 32 = 8x

=> -32/8 = x

=> -4 = x