Need help, will give the brainliest to whoever can help me. Pre-calc/Trig

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

Elizabeth claims that the fourth root of 2 can be expressed as 2^m since (2^m)^n = 2. find the values of m and n for the case where elizabeth's claim is true.

Evaluate 5 + 6 · 2 – 8 ÷ 4 + 7 using the correct order of operations. a. 22 b. 11 c. 27 d. 5