Triangle A B C is reflected across the line of reflection m to form triangle A prime B prime C prime. Triangle A prime B prime C prime is rotated about point B prime 270 degrees to form triangle A double-prime B double-prime C double-prime.
Which rule describes the composition of transformations that maps ΔABC to ΔA"B'C"?

the way you can figure this out is by looking at the figures and finding what transformation came first because of the number of prime notations on a letter in a figure. in this case is was ABC first then A'B'C' then A''B''C''

using that we can now determine the order of how the composition will be written. the first step of the composition is the left most part and the last part of the composition is the right most part. basicly the order is left to right.

we see that figure ABC is reflected across the line m to create the figure A'B'C' relections are written like r for the relection and the sub letter is the line the figure is reflected across to in this case it would be written as r sub m meaning that r sub m is the 2nd part of the composition.

the 2nd step in the composition is when figure A'B'C' turns into figure A''B''C'' the way we find out its transformation is determine whether it was slid or if it was rotated aroound a point of rotation. here we have a rotation. now we got to determine what the center of roation is. in this case its B'. looking at the options there is no negative -90 degrees which means that the rotation happened counter clockwise because all valuse are positive. counter clockwise is to the left. now simple math figure A'B'C 180 degrees would make it need 90 more degrees so 180+90=270 thats the degree of the roation around point B'

rotations are written as R sub point of rotation, __ degrees. in our case it is r sub B', 270 degrees. this is the second step so it will be on the right of the equation. the full equation turns out to be R sub B', 270 degrees composition of transformations r sub m.

it must be that way because if you rotated the figure first then reflected it it would look like an entirely different image.

pls give brainliest