find the area of an Equalateral triangle (regular 3-gon) with the given measurement 9 inch perimeter? A= sq. in.

Step-by-step explanation:

P= 3a ( a is the side of triangle)

a=P/3 =3

A=√3/4 a^2

  = √3/4 * 9 = 3.9 sq. inch

b

step-by-step explanation:

80π/3 or about 83.775

step-by-step explanation:

since a cone is 1/3 of a cylinder, we need to find the base's area. since area = πr^2, we get 16π. then, multiplying this by 5, we get 80π. dividing by 3, since the cone's volume is 1/3 of that of a cylinder's, we get 80π/3.

hope this !