Solve Pattern Brain Teaser: 3*1+3*2+3*3+3*4

[ArielGenesis]

if
1*2=2*1
2*3=2*1+2*2
3*4=2*1+2*2+2*3
4*5=2*1+2*2+2*3+2*4

then
3*1+3*2+3*3+3*4=?

 

[Jimmy Snyder]

Answer is whited out:

2 * (1 + 2 + 3 + 4 + 5)

 

[ArielGenesis]

umm. I'm sorry but i guess i suppose to rephrase the question,
?=3*1+3*2+3*3+3*4

in form of
1*2
2*3
and
3*4

 

[Jimmy Snyder]

Answer whited out:

5 * 6

 

[ArielGenesis]

?=3*1
?=3*1+3*2
?=3*1+3*2+3*3
?=3*1+3*2+3*3+3*4
?=3*1+3*2+3*3+3*4+3*5

 

[RandallB]

?=3*1
?=3*1+3*2
?=3*1+3*2+3*3
?=3*1+3*2+3*3+3*4
?=3*1+3*2+3*3+3*4+3*5

1*3
3*3
3*6
5*6
5*9
7*9
7*12
9*12etc - Good one

 

[ArielGenesis]

at, that's what i am looking for