Replace * with a monomial in such a way, that the trinomial becomes a perfect square.
16y + * +81

Assume that a population of 50 individuals has the following numbers of genotypes for a gene with two alleles, b and b: bb = 30, bb = 10, and bb = 10. calculate the frequencies of the two alleles in the population’s gene pool.

Which of the following three dimensional figures has a circle as it’s base

Set $r$ is a set of rectangles such that (1) only the grid points shown here are used as vertices, (2) all sides are vertical or horizontal and (3) no two rectangles in the set are congruent. if $r$ contains the maximum possible number of rectangles given these conditions, what fraction of the rectangles in set $r$ are squares? express your answer as a common fraction.