Provide the first six terms of the following sequence: t1=81 tn=1/3tn-1

We get tne n-th term with: tn=1/3tn-1

We know that the first term is t1=81, so 81=1/3t*1-1

81=1/3t-1

82=1/3t

82*3t=1

3t=1/82

t=1/82*3=1/246

The second term is: 1/

2*(1/246)*2)-1

We get the third term by replacing n with 3 and so on...

check the picture below.

well, the angle at the vertex d is clearly not a right-angle, let's check for the one at the vertex f which does look like,   however if it's indeed, that means ef is perpendicular to df, in which case their slopes will be negative reciprocal of each other.

so the negative reciprocal of the slope of ef is 1, however the slope of df is not 1, is 1/2, so nope, they're not perpendicular lines.

answer:

c. the third graph