Emir is standing in a treehouse and looking down at a swingset in the yard next door. The angle of depression from Emir's eyeline to the swing set is 31.43', and Emir is 11 feet from the ground. How many feet is the base of the tree from the swingset? Round your answer to the nearest foot.
15 feet

20 feet
18 feet
24 feet

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

Exercise: counting committees 0.0/2.0 puntos (calificable) we start with a pool of n people. a chaired committee consists of k≥1 members, out of whom one member is designated as the chairperson. the expression k(nk) can be interpreted as the number of possible chaired committees with k members. this is because we have (nk) choices for the k members, and once the members are chosen, there are then k choices for the chairperson. thus, c=∑k=1nk(nk) is the total number of possible chaired committees of any size. find the value of c (as a function of n ) by thinking about a different way of forming a chaired committee: first choose the chairperson, then choose the other members of the committee. the answer is of the form c=(α+nβ)2γn+δ. what are the values of α , β , γ , and δ ?

Determine if each number is a whole number, integer, or rational number. include all sets to which each number belongs. 4. -12. 5. 7/8