Find the area of an area of an equilateral triangle (regular 3-gon) with the given measurement 9-inch perimeter. a=sq. in.

Area = side^2 * sqrt(3) / 4

If 9 inch perimeter then side = 3

Area = 3^3 * sqrt(3) / 4

Area = (9 / 4) * sqrt(3)

Area = 3.897114317 square inches

Step-by-step explanation:

hello from mrbilldoesmath!

answer:

a(n) - a(n-1) -3

discussion:

this ones a bit interesting. given a(n) = 5 - 3n consider this:

a(n-1) = 5 - 3(n-1)

          = (5 - 3n) + 3             => but a(n) = 5 - 3n, the first term

          = a(n)   + 3                 => subtract 3 from both sides

a(n-1) -3 = a(n)  

or

a(n) - a(n-1) -3

you,

mrb

the correct answer is semicircle

step-by-step explanation:

the answer is semicircle because the shorter arc joining two points on the circumference of a circle is known as the minor arc, the larger arc is called the major arc, and a semicircle is a half circle, formed by cutting a whole circle along a diameter line.

hope i .