What is the common difference, the general term equation, and the 12th term of the arithmetic sequence?

hint: a_n=a_1+d(n-1) , where a_1 is the first term and d is the common difference.

-7-(-2)=-5
-12-(-7)=-5
the common difference is -5

Shortest side: xside two: x+26side three: 2xwork: x+x+26+2x=1304x+26=130 -26 -264x=104(4x=104)/4x=26check: 26+26+26+52=130shortest side length is 26 feet

I'm a bit puzzled here because they did not provide you with any measures of the other angles, so i am unable to provide a theorem or postulate to support my answer, but i'd say 90 degrees because it looks closer to a right angle than anything.