In a lecture hall at a collage, the number of seats per row increased at a constand rate. the professor counts 21 seats in row 3 and 33 seats in row 7. how many sets are there in row 18?

  66 seats

Step-by-step explanation:

The rate of increase is ...

  (change in seats)/(change in rows) = (33 -21)/(7 -3) = 12/4 = 3 . . . seats/row

Then row 18 will have (18-3)·3 = 45 more seats than row 3, hence ...

  21 + 45 = 66 . . . . seats in row 18

An explicit formula for the number of seats can be written as ...

  s = 21 +3(n-3) = 12 +3n

For n=18, this is ...

 s = 12 + 3(18) = 12 +54 = 66 . . . seats in row 18

step-by-step explanation:

given that there are two triangles j'k'l' and jkl>

the former is got by dilating the second one.

when drawn on a grid, (graph paper) coordinates of vertices of first triangle is

(6,12)j, (9,6)k and (12,9)l

side jk has length = distance between j and k

=

side j'k'=distance between j' and k'

=

ie j'k'l' has sides 1/3 of that of corresponding sides of jkl.

hence scale factor of 1/3 is used to get j'k'l'from jkl

in the attachment.   i didn't see your choices.   the word which means there is choices.

step-by-step explanation:

(x,y)

x tells you how much left or right you go from the origin

y tells you how much down or up you go from the origin

so for example (-3,2), you go left 3 and up twice. i denoted which of the ordered pairs is which in my graph.