Please solve number 15 and 16, i know that the answers are 42° and 18° but I need to know how to get to that answer. If the answer is correct I will give brainliest. Thank you.

Atriangle has a side lengths of 18cm, 80 cm and 81cm. classify it as acute obtuse or right?

Joel wants to buy a new tablet computer fram a store having a 20% off sale on all tablets. the tablet he wants has an original cost of $190. he also wants to make sure he has enough money to pay the 5% sales tax. part one joel uses the incorect expression 0.95(190)(0.8) to calculate that the tablet will cost him a total of $144.40. describe his error and write the correct expression part two how much will joel pay for the tablet show your work if you answer this question correctly you will receive a prize of 99 points good luck

The total number of dental clinics total for the last 12 months was recorded