I neeed the answer pls

2.30+0.4-0.88+1.33 can u explain the answer to this why the answer is 3.15

Marie drew the triangle shown. she wants to draw a second triangle that is different from this one. use the drop-down menus below to complete the statements about the second triangle.

Given the following sampling distribution of one mean with a sample size 49, from a normally distributed population,find the population standard deviation, o.79828588912497