Encyclopedia britannica's list of 20 world class orchestras include the following from the united states: boston symphony orchestra, cleveland orchestra, chicago symphony orchestra, los angeles philharmonic, new york philharmonic, philadelphia orchestra, and the san francisco symphony. choose 5 at random from the list of 20 for a benefit cd.
what is the probability that the collection will include at least one group from the united states?
at least 2 from the united states?
that all 5 will be from the united states?

it's a question with 3 different parts. explain how you did it. : )

trapezoid

step-by-step explanation:

first i plotted all my points on a grid graph

i made sure all of them were in the correct quadrant

then i saw it was a trapezoid or a quadrilateral

geometry: triangles

solvers

lessons

answers archive

call the larger triangle abc

then the smaller triangle cde is similar to abc (all angles are equal, aaa).  

ab is the side that is 36, and we wish to find de, the side corresponding to ab

area_cde = area_abc - area_cde --> area_abc / area_cde = 2

let x=length of de

ratio of areas = (ratio of sides)^2

+2+=+%2836%2fx%29%5e2+

+2+=+1296%2fx%5e2+

++x%5e2+=+1296%2f2+=+648+

25.45584