Each figure is a regular polygon. Expressions are given for two side lengths. Find the value of x. Help is highly appreciated!
Will give brainliest.
All 3 problems with brief explanations would help out, I’m here to learn and not get plain answers :D

Scores on the cognitive scale of the bayley-scales of infant and toddler development range from 1 to 19, with a standard deviation of 3. calculate the margin of error in estimating the true mean cognitive scale score, with 99% confidence, if there are 12 infants and toddlers in a sample.

Consider the triangle. which shows the order of the angles from smallest to largest? angle a, angle b, angle c angle b, angle a, angle c angle b, angle c, angle a angle c, angle a, angle b

Nina has prepared the following two-column proof below. she is given that ∠oln ≅ ∠lno and she is trying to prove that ol ≅ on. triangle oln, where angle oln is congruent to angle lno nina made two errors in the proof. identify and correct the errors.