AO ⊥ (BCD)
OB = OC = OD = 12
m∠ACO = 20º
BD = CD = BC
Find: V and Surface Area of a triangular pyramid

This is what i found “an explicit formula designates the nth term of the sequence, as an expression of n (where n = the term's location). it defines the sequence as a formula in terms of n. this example is an arithmetic sequence(the same number, 5, is added to each term to get to the next term).” i hope this you for what your looking for. can you plz mark me brainliest?