The sum of the interior angles of a polygon is 9x². If x is 3 greater than the number of side of the polygon, how many sides does the polygon have?

17

Step-by-step explanation:

This is a very neat problem -- for teachers.

Let the number of sides = y

The sum of the interior angles is 180*(y - 2)

We are told that this sum equals 9x^2

So far the equation is

(y - 2)*180 = 9x^2                   Divide both sides by 9

(y - 2)*20 = x^2                       Remove the brackets on the left.

20*y - 40 = x^2

We need another fact. We get that from the statement that x is three greater than the number of sides (y). Therefore y = x - 3

20*(x - 3) - 40 = x^2

20x - 60 - 40 = x^2       Combine like terms on the left

20x - 100 = x^2             Bring the left side to the right side.

0 = x^2 - 20x + 100      You have a quadratic.

a = 1

b = - 20

c = 100

When you solve the quadratic equation, you get

x = 20

Therefore the number of sides is 17.

dc=6 square root of 3 and ac is 12 square root 3

c and d

step-by-step explanation:

square root of 3/2 = 18/c

cross multiply to get 18*2=√3*c

36/√3 * √3/√3 = c

c= 36*√3/3

c=12√3

answer:   (s+1)(s+4)

step-by-step explanation:

factor s2+5s+4

s2+5s+4

=(s+1)(s+4)