Which sequences are geometric? check all that apply. –2.7, –9, –30, –100, –1, 2.5, –6.25, 15.625, 9.1, 9.2, 9.3, 9.4, 8, 0.8, 0.08, 0.008, 4, –4, –12, –20,

–2.7, –9, –30, –100, ...

–1, 2.5, –6.25, 15.625, ...

  8, 0.8, 0.08, 0.008, ...

Explanation:

A geometric sequence is a sequence with the ratio between two consecutive terms constant.  This ratio is called the common ratio.

now check all the sequence one by one.

For sequence –2.7, –9, –30, –100, ...

r =

=

=

We see that, all the ratios are same.

So this is geometric sequence.

For sequence   –1, 2.5, –6.25, 15.625, ...

r =

This is also geometric sequence.

For sequence  9.1, 9.2, 9.3, 9.4, ...

In this sequence, common ratio  is not same.

So, it is not a geometric sequence.

For sequence    8, 0.8, 0.08, 0.008, ...

Common ratio is same so, it is geometric sequence.

For sequence   4, –4, –12, –20, ...

Common ratio is not same. So, it is not geometric sequence .

135 is your answer

step-by-step explanation:

try 180 times three then divide that number by 4 (sides) to get your answer. im glad to : )

tell you what. i'll find the length of the medians and you can fill in the blanks where they belong.

br

b = (2a,0)

r = (a/2,b/2) remember these things are medians. they go to the 1/2 way point of the line opposite the vertex they face.

br^2 =   (2a - a/2)^2 + (0 - b/2)^2

br^2 = (3/2 a) ^2 + b^2 / 4

br^2 = 9/4 a^2 + b^2 / 4   we need to find some relationship between a and b.

let's try ab = bc  

ab = 2a

bc = (2a - a)^2 + (b - 0)^2

bc = sqrt(a^2 + b^2)

ab = bc

2a = sqrt(a^2 + b^2) square both sides.

4a^2 = a^2 + b^2 subtract a^2 from both sides.

sqrt(3a^2) = sqrt(b^2)

sqrt(3)a = b

let's put b into br^2

br^2 = 9/4 a^2 + 3b^2 / 4

br^2 = 12 a^2 / 4

br^2 = 3a^2 

br = sqrt(3) * a

cp

c = (a,b) ; p = (a,0) this is another application of the distance formula, and it is a good one.

cp^2 = (a - a)^2 + (b - 0)^2

cp^2 = 0 + b^2

cp^2 = b^2 which you can see from the diagram. 

cp = sqrt(b^2)

cp = b but b = sqrt(3) * a 

cp = sqrt(3)*a

aq

a = (0,0)

q = (3/2) a, b/2

aq^2 = (3a/2 -0)^2 + (b/2 - 0)^2

aq^2 = 9a^2/4 + b^2/4

but b = sqrt(3) * a 

aq^2 = 9a^2 / 4 + (sqrt(3)*a)^2 /4

aq^2 = 9 a^2/ 4 + 3 a^2 / 4

aq^2 = 12 a^2/4

aq^2 = 3 a^2

aq = (sqrt  3) * a which agrees with the other two.