Find the area of the triangle

What is the 12th term of b(n)=-4-2(n-1)

Rose bought a new hat when she was on vacation. the following formula describes the percent sales tax rose paid b=t-c/c

Asource of laser light sends rays ab and ac toward two opposite walls of a hall. the light rays strike the walls at points b and c, as shown below: what is the distance between the walls?