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Help #2

NotSoSmart  Mar 9, 2018
 #1
avatar+90968 
+1

3. 

a1  = -4      a2  =  8     a3  =  -16

Note, NSS...it appears that we are multiplying each term by -2  to get the next term

 

So.....the "formula"  appears  to be

 

-4 * (-2)n-1   

 

The  5th term  is     -4 *(-2)(5 - 1)  =  -4 * (-2)  =  -4 * 16   =   -64

 

 

4 .   This is a geometric series in disguise

 

The side of the the nth triangle  is given by

 

(50) * (.80)n - 1

 

We could use some fancy math here...but let's just do this

 

Side  of  2nd trangle  =  50 * (.80)(2 - 1)  = 50 * (.80)   =  45

Side of third triangle  =  45*.80  =  36

Side of 4th triangle  =  36 * .80  = 28.8 inches

 

 

cool cool cool

CPhill  Mar 9, 2018

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