Given the area of a regular octagon is 216m2 with a side length of 9, find the length of the apothem.

The customer price index(cpi), which measures the cost of a typical package of customer goods, was 208.8 in 2011 and 244.1 in 2016.let x=11 corresponding to the year 2011 an estimate to cpi into 2013 and 2014. assume that the data can be modeled by a straight line and the trend to continue idenfinitely. use data points to find such a line and then estimate the requested quantities

Prove that 16^4-2^13-4^5 is divisible by 11.

Which geometric principle is used to justify the construction below?