What is the next number 1,1,2,4,3,9,4

Which expression is equivalent to (3^2)^-2 a.-81 b.-12 c.1/81 d.1/12

Which triangle congruence postulate or theorem justifies my claim that the steps i made using construction paper and scissors produce an isosceles triangle? was it sss, sas, asa, aas, or hl?

Asphere has a diameter of 10 in. what is the volume of the sphere?