A study of a local high school tried to determine the mean number of text messages that each student sent per day. The study surveyed a random sample of 81 students in the high school and found a mean of 163 messages sent per day with a standard deviation of 64 messages. At the 95% confidence level, find the margin of error for the mean, rounding to the nearest whole number.

With these 5 geometry questions! pls 1.)quadrilateral abcd is inscribed in this circle.what is the measure of ∠a ? enter your answer in the box.°2.)quadrilateral abcd is inscribed in a circle.what is the measure of angle a? enter your answer in the box.m∠a= 3.)quadrilateral abcd is inscribed in this circle.what is the measure of angle b? enter your answer in the box.m∠b= °4.)quadrilateral abcd is inscribed in this circle.what is the measure of angle a? enter your answer in the box.°5.) quadrilateral abcd is inscribed in this circle.what is the measure of angle c? enter your answer in the box.°