PLS PLS someone help asap Calculate the Standard Deviation of the following set of data.

For the following geometric sequence, find the recursive formula. {-80, 20, -5, } i need : ')

Hi, can anyone show me how to do this problem? 100 points for this. in advance

In a 45-45-90 right triangle, what is the ratio of the length of one leg to the length of the other leg? а . 1: 2 в. 2: 1 с. 2: 1 d. 1: 1