#1 is confusing and i messed up a couple times, needed

What is the value of the expression below? (81^2)^1/8

50 points and will mark brainlest if you were constructing a triangular frame, and you had wood in the length of 4inches, 4 inches, and 7 inches, would it make a triangle? would you be able to create a frame from these pieces of wood? yes or no? = explain your mathematical thinking:

Fill in the missing exponents in each box and show how you found the answer. (4 points: 2 points for each correct answer with work shown) c. (9^4)^? =9^1 d.(5^? )^3=5^1 *question marks represent the boxes