The triangles below are all equilateral and each smaller triangle has a side length half that of the next larger.

If the pattern continues, what is the total perimeter of all the triangles?

I keep getting 21, but its wrong :(

Question

The triangles below are all equilateral and each smaller triangle has a side length half that of the next larger. 

If the pattern continues, what is the total perimeter of all the triangles? 

I keep getting 21, but its wrong :(

superhelp101 · Answer

@Compassionate :)

superhelp101 · Answer

|dw:1432788819070:dw|

random231 · Answer

total perimeter of these three triangles is no doubt 21

superhelp101 · Answer

ikr! I don't understand my teacher marked it wrong :(

random231 · Answer

but i think whats asked in the question is the sum of all the triangles following this pattern. Which means you have a infinite GP series

superhelp101 · Answer

so is that |dw:1432789511714:dw|