.. List the 15th
and 19th
triangular numbers.

See below in bold.

Step-by-step explanation:

The formula is Tn = n(n + 1) / 2

The first triangular number is 1(1+1) / 2 = 2/2 = 1.

So the 15th = 15(15+1) / 2 = 120.

and the 19th = (19 * 20) / 2 = 190.

the central idea is that:

individuals should refuse to cooperate with institutions they believe unjust.

thoreau felt  that governments were more often agents of corruption than justice, even democracies, and that just because the majority feels a certain way does not make it just or correct in absolute terms. he uses the fact that slavery exists in our democracy to support this idea.

he goes on to say that, as a result, people should live true to their own internal laws regarding right and wrong, as a product of reflection and a moral life, rather than following every law that society imposes. 

step-by-step explanation:

which expression represents the approximate length of bc?

step-by-step explanation: